(Courtesy of everyone in this thread on Google + (add me if you can't see it).)
This took 2 and a half hours to put together.
1. If left in sunlight, always appears in shadow when next seen.
2. Bookmarks rot within 1d6 days
3. Information critical to understanding the rest of the book is written on the endpapers in ink that can only be seen in the light of a burning Hand of Glory.
4. Earmarks straighten out whenever the book is left in darkness.
5. Misquotes other occult books investogator is familiar with but author seems to mistranslate parts of sentences into an unknown tongue not understand that they are doing it
6. Gives those using it a papercut every damn time.
7. Is a palimpsest in which the original writing can only be seen under the light of the harvest moon.
8. Waterproof, but not blood proof.
9. Sprouts centipede legs and scuttles off if given half a chance
10. Consumes other books when shelved with them. Its ink begins to fade unless it eats another book at least once a week.
11. The whole text is a palindrome when translated to enochian script.
12. Contains only information reader already knows, thought written in an intoxicatingly majestic style. The book actually removes this information from the reader's mind as s/he reads.
13. Is overdue from the library of Gorlex the Unsavory. And you don't want to hear about the late fees ...
14. Every time it is opened it steals one year from the far end of the reader's life.
15. Pages are numbered incorrectly (i.e. out of sequence), but bound in numerical order, making it a tremendous pain in the ass to use.
16. Chapter beginning illuminations switch persons shown whenever one is copied.
17. If read backwards, the book is surprisingly breezy easy reading (taking just all night to read!), and reveals one important fact about an important NPC yet to be met that the NPC would rather not be known.
18. Moves bookmarks d6 pages towards the end if the book (and reading the "skipped" pages reveals the most important and terrifying truths)
19. Text is set in two different colors, but each color is from three different kinds of ink. Reading the parts that match kinds of ink gives you the real name and location of the author, who is giving instructions as how to free him from his demonic gaol encoded in the whitespace.
20. Front cover: white goatskin, back cover: black goatskin.
21. Fake student text from a wizard academy: The first thirty pages are an incomplete tome on the effect on aetheric currents on arcane casting. The remainder of the book is succubus-on-succubus porn.
22. When used to wedge something shut, gains thousandfold weight. This is usual at risk of architectural integrity, and the book is often found at the base of fallen towers.
23. Several pages are stuck together. Breaking the seals frees a plethora of literary and allegorical daemons to plague the reader.
24. When burnt, creates horrid smoke that when breathed imparts the book's content on everybody witnessing the burning (200' radius, but always happens to the person igniting the fire). On a failed save vs magic, victim is compelled to recreate book, including dark rituals to bind the preserving spell to the book again.
25. The pages of the book are impregnated with hallucinogens, which will kick in, in 1D4 x 10 minutes, rendering the contents of the book frighteningly real.
26. Book is obviously new in every respect but contains vast amounts of detailed minutiae about world historical events which are recorded nowhere else and which, if checked against physical evidence, are demonstrably true. The author's name is on the spine.
27. The book has a gatefold section that really is a gatefold, opening a portal to whatever vista is illuminated on the page. Blue skidooed, we can too!
28. Reading causes nightmares for distant family member.
29. Touching the book causes eczema to develop on readers skin in 2d6 days.
30. When read in the original language of the first edition it includes subtle linguistic references that turn the context into a romantic epic.The copy the players have is the 4th edition, which reads as the worst kind of textbook.
31. The contents of the book don't "sink in". The reader learns nothing from reading, however the last person to touch it before them learns as the new reader reads.
32. If opened to a random page, you can read an awkward secret about someone within visual distance.
33. Both front and back are covers. If read as if front 1 is the real front, it is on some utterly banal and boring topic (crop yields, tax law, whatever), but if read from front 2 it is the occult tome.
34. The book forms part of some Borgesian labyrinth a la The Garden Of Forking Paths or House Of Leaves.
35. It is a loose-leaf folio that if rearranged becomes another, completely different occult tome.
36. Spine and cover of book lined with lead; treat as club when used in combat.
37. Gains a chapter on the life history of anyone that possesses the book for more than a day. This history is correct, other than one major untruth.
38. The book's index is wrong and changes to a useful index of a book standing left of it when put there for a day.
39. Reading any entry in the bibliography aloud summons that particular book, but also telegraphs your location to the wizardly owner of said book.
40. If held in front of a mirror, a duplicate copy will be created in another random time and location
41. Is still a work in progress despite having been printed & bound. Passages are constantly being rewritten, illuminations added, diagrams redrawn.
42. Book is not subject to gravity if opened and placed in the air. It will support up to 10 pounds while so levitating, and its pages are immune to wind-flutter (that is, it will keep its place).
43. The book details every event of the reader's life, in reverse, starting with their gruesome death at the hands of the book's next reader.
44. The book's content is so mundane that while reading it you're immune to any and all magical effects. If you're a magical creature trying to read the book, it's pages seem to be empty (this includes all characters being able to cast spells).
45. Certain parts can only be accessed if read in a mirror (the cover also has a mirror affixed, perhaps, to act as a clue).
46. When the book is opened spiders crawl towards it.
47. If read within an hour after killing a humanoid:human - Text is not justified, every page is written margin to margin in writing with sentences running off.dwarf - Touching the text will reveal raised lettering not matching what is written on the page. The sentences in raised lettering will reveal the consciousness of the dwarf's spirit. If read to the end of the book the dwarf's spirit will cease to exist.elf - When opened, the book will absorb the breath of a reader poring over the text. The reader will find it progressively harder to breathe the more time is spent reading. Closing the book will return the reader's breathing to normal.orc - Reader does not feel any aches or strains from bending to read the text for extended periods, but immediately feels them after closing the book.
48. The book erases readied spells out of the reader's mind and puts them on the pages; the book can only read safely as a spellbook with a custom Read Magic variation (and the book containing that is well, well hidden by the M-U that owns both books).
49. Illustrations within the book are real and may be grasped and removed from the book, though this is not clear unless an attempt is consciously made to grasp them.
50. Dead bodies putrefy unnaturally fast when the tome is close to them.
51. The agnostic topic of the book makes the reader function as the focus of a turn undead spell, only it affects clerics. This effect is ongoing while the book read, plus 1d6 hours after. (Turning at reader's level / hit dice)
52. The information the reader seeks is contained in full inside the book, but only as a subplot in a metaphorical tale that conclusively proves with cool reason and irrefutable logic that the values most dear to the reader are utterly utterly wrong. So convincing is the argument that it forces a reversal of alignment, causes the faithful to lose their faith, the godless into devouts, the selfish to become selfless, the kind to be cruel and so on.
53. If you hold the book upside down before opening it to a random page it shows a map on the left hand page of exactly where you are standing. The surrounding region on the map will have a 50% chance of showing any hidden or secret features. Nearby creatures are shown as appearing and disappearing ink spots on the map. It gives the reader a migraine after 1D6 turns of continuous use.
54. Cover assumes the color of the eyes of the last person to read it all the way through.
55. The skin binding is unnaturally warm, and shivers pleasantly when stroked. Owners of the book often caress it in a manner that becomes increasingly lascivious the longer they possess it.
56. The second to last chapter contains a number of really funny jokes, for a five year old's kind of humor.
57. The stitching is of dubious quality - whenever opened there is a percentage chance (equal to the readers STR score) that a random page falls out. The original content of this page changes to contain a contract (in an ancient script) that explains the readers soul is now property of a supernatural power, who will contact the PC within 1d4 days to demand a nefarious service.
58. Tearing out and eating a page of the book pulls you into the world it describes. If someone tears and eats the page whose contents you are travelling in, both save vs magic to avoid exploding into a gory picture filling the pages magically replacing the missing ones.This book gets more and more violent and gory over time, until it reaches a style that even James Raggi thinks is unbearably gross.
59. Oh geez now you've got booklice. Only it takes about a week before you notice, and by then everything is infested. *EVERYTHING*
60. When hidden clasp in binding is unfastened book magically unfolds into adjustable flight of stairs up to 100 feet in height.
61. The book is a fascinating read that keeps you up all night. You will be dog tired the next morning and not be able to memorize spells. Save vs. magic the next night to avoid continuing to read the book. Apply normal rules for sleep deprivation except for falling asleep. Reading the whole book requires seven nights. Removing the book from the vicinity of the victim induces nightmares for 1d4 weeks.
62. If read from cover to cover, silently or otherwise, over any period of time, so long as it is read sequentially, an avatar or god featured in the tome is summoned.
63. The tome's text writhes upon its vellum pages as it's read, almost as if the letters are trying to break free. If a PC touches the writing, there's a 4 in 6 chance that the characters will adhere to their skin, marking their body part indelibly with the arcane text (unless removed by a Remove Curse spell).Rumor has it that a shadowy cabal of mages trades in "living grimoire:" severed body parts (mostly hands and arms, though the occasional torso or head shows up in their collections) affected by the book's curse.
64. The book is bound in the brain matter of a dead wizard or psychic. The book details the life of this person, in a style that is unnaturally compelling to the reader.As the book is read, spells or powers are "unlocked" in the reader and the reader is able to envision and relive events from the author's life not featured in the work.Upon finishing the book, the reader's own mind is wholly replaced with the consciousness of the dead wizard or psychic; meanwhile the reader's own story is recorded in the book, stored there until they replace the next unsuspecting reader.
65. "Careful study and another successful Geology roll may lead to a single point of Sanity loss, if the Keeper chooses, as the form in the “geode” (on the cover) clearly appears to be a cross section of a worm-like creature, unknown to science, curled in around itself." -Brett Kramer "Masks if Nyarathotep Companion"
66. Half of book is written in red ink, the other half in green - these writings are at war with each other. Pages change with the rise and fall of textual empires.
67. Book hates the spoken word, and will snap shut for 1D4 Turns (often maliciously trying to take the fingers of the reader) if anyone speaks within 20' of it while it is open.
68. the book is still redlined. The scathing remarks of the editor hold the real secrets the tome promises to unlock.
69. The book's script seems to burn with an unnatural urgency. Reading more than a page in an hour causes temporary blindness.
70. Seems to contain innocuous and banal facts about the everyday world. Things everyone knows anyway. The reader dreams of these things for d6 +2 nights, each night these facts just seem a little stranger and implausible. On the last night the reader can no longer believe the world around them is real.
71. All of the pages of the book are snakeskin.
72. The book has tiny little holes in every page encoding a dissenting view in braille.
73. Touching the endpapers triggers a Save vs Death.
74. The dedication page contains the name of a PC.
75. The book is a meme seeking a physical incarnation. Its manifestation is recent, and thus far is a literal zygote that has only acquired a spine and some leaves, unsure of its final biology. Each time it comes into contact with another living being if will acquire a feature of its biology.
76. While reading the book, everyone within 30 feet of the reader is filled with an insatiable desire to brutally mutilate the reader. This effect lasts for 1d3 turns after the reader stops reading.30 minutes after closing the book, the last reader is filled with an uncontrollable desire to start reading again.
77. The book is a real slog, poorly written with pertinent information scattered throughout the pages, incorrect page references, a slanderous index and incomplete chapters. But fanning the pages to send a breeze across the reader's face is instantly refreshing and removing all weariness.
78. The work is written in a recognizable and authentic but seemingly impossible form of Middle English/Middle Common (i.e. words and spellings coined years later appear, before their etymological antecedents, archaisms and syntactical structures derived from languages thought lost during the period appear).
79. The information sought by the reader is not to be found in the written word, but coded in the delicious booksmell that rises from each page.
80. Every page has a small section of simple but utterly opaque magical text in the middle of the page. Arranged around this text are three elaborate conflicting commentaries. In fact it is three different spell books in one. If the reader tries to use more than one commentary to interpret the spell on any given page, she will arrive at a definite and nuanced interpretation. But when the spell is cast it will have a 50% of affecting her as a confusion spell.
81. Because nobody's said it yet:"It's a cookbook!" (disguised as an occult tome, to keep the recipes proprietary)
82. Cursed necromantic tome. For each spell learned, the user comes one small step closer to being a living mummy.
83. The book details the lascivious and inappropriate sexual encounters and depravities of all of the spiritual and political leaders of the nearest hamlet or village (but not city), including detailed accounts of specific acts and encounters between those leaders.It is absolutely certain that the book will be found and read by someone who lives in the community.50% of the stories are true, so the book is a dangerous weapon of blackmail and gossip amongst the locals.The contents change whenever the book approaches another village or hamlet.
84. After reading the book (all effects):In 1d6 days fingernails become blackened and soft. In 2d8 days 1d6+1 teeth dangle and fallout 1d3 days later. In 1d8 days hair becomes brittle, thin, and white. In 1d20 days 1d100 cysts grow on body.
85. The book contains the names of all witches known and unknown, throughout the world, organized by region and date of birth. It contains only the current generation of witches.
86. The book is actually a spying device. The owner of the counterpart can see you whenever you open the book.
87. A bestiary in the form of a pop-up book, if a page is removed and thrown to the ground, it becomes an animate, life-size version of the illustration.
88. It's a trashy novel by a setting-equivalent Matthew Reilly. Drains 1 point of intelligence for every hour you read it, make a save against Will/Paralysis to put it down.Upside down, it's a proper grimoire.
89. The book contains all the results of all major sport events and games of chances in the realm for the next 50 years. Someday a crazy wild eyed magician and a kid will show up asking about this book.
90. The book was not written: it is an author, and scholars who have claimed to read it are, in fact, its works.
91. It's an epaper book with 1d6 weeks of battery power left. It has 100 various books stored on it, which require their own table to roll for.
92. Its pages are made from the wrappings of a certain much sought-after mummy, making the book worth fifty times as much as raw materials for spells than for what's written in it.
93. The book is a polymorphed halfling. If you put it in your knapsack, it will eat your rations.
94. The books is seemingly endless (as if each page had a thickness of 0). every time a new section of it is read, it will be about someone who has read the book before, and describe a future action of the person, as if describing a past even.The book deson't predict the future, however. Instead, it tries to compel its readers to do its will. Anyone who tries to defy what is written must save vs spell (or will save, or what have you) or act as the book dictated. The book itself is completely impervious to damage, and can only be destroyed by an illiterate person.
95. In the back of the book is a collection of love letters sent between two ancient feuding Persons Of Interest in the game world. There is talk of a love child hidden away somewhere, that hasn't been mentioned in history before. Finding this child or their descendants will cause great turmoil.
96. Upon finishing the book the reader's intelligence score increases to 100 and they spend the next 3 days feverishly babbling, scribbling notes, and attempting to collect resources to construct a "space bridge".There is a 5% chance they successfully detail or build the bridge.Regardless, at the end of 3 days their intelligence returns to normal, and while they remember possessing the knowledge of how to build the space bridge, they are painfully aware they no longer know how to build the device or what it's function/purpose would be.Reading the book a second time has no effect.
97. If you fall asleep reading the book, you'll wake up fully refreshed and invigorated 12 years later (unless woken up/killed inbetween).
98. Concealed under the cover is a map to the Underworld.
99. From each page of the book exudes fresh air, as if from a clearing. The clearing the book draws air from smells like an old moldy library.
100. The tight, crabbed scrawl filling the thousands of pages within aren't words, they're sounds. Rubbing a violin bow, or a phonograph needle gently across the pages will produce sounds. The whispers of the gods as they made the universe. [insert d100 chart of possible effects].