Book of 99 slot
Book of 99 is a Relax Gaming slot released on 4 May 2021, with 5 reels, 3 rows and 10 paylines and a cast of heroes and villains from Greek myth. A book symbol is both wild and scatter, and three or more open 10 free spins with a randomly chosen expanding symbol. The twist is the number in the title: every book that lands in the base game is counted, and reaching 99 starts the free spins without any scatter trigger at all.
Editorial note: this guide explains how Book of 99 works. Rules, features and payout figures are set by the studio and can differ between operators and game versions, so check the game’s information panel before you play. Slots are games of chance, and nothing here predicts results. Availability at Fortune Games can change.
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Book of 99: key facts
| Studio | Relax Gaming |
|---|---|
| Released | 4 May 2021 |
| Reels and paylines | 5 reels, 3 rows, 10 paylines |
| Top line payout | Top character symbol: 500x stake for five on a payline |
| Book symbol | Wild and scatter in one; substitutes for the other symbols |
| Free spins | Three or more books: 10 free spins |
| Book collection | Books landed in the base game are counted; 99 collected books trigger 10 free spins |
| Special expanding symbol | One symbol chosen at random before the free spins; when it lands it fills its reel and pays regardless of the paylines it sits on |
| Autoplay and turbo | Not available at sites licensed in Great Britain; UK rules require at least 2.5 seconds between the start of one game cycle and the next |
| UK stake rules | UK rules cap online slot stakes at £5 a spin, or £2 if you are 18 to 24, at every site licensed in Great Britain |
| RTP | Shown in the game’s information panel |
| Series | Stand-alone |
All values (Bet Levels, Maximum Wins etc.) mentioned in relation to this slot game are subject to change at any time.
How Book of 99 plays
The game takes the familiar five-reel, ten-line book layout and dresses it in ancient Greece. Card royals from A down to 10 make up the low-paying symbols, while mythological characters, heroes and monsters alike, pay the most. Line wins are paid along the 10 paylines. The book does two jobs: as a wild it fills gaps in line wins, and as a scatter it is the key to the bonus. What sets the base game apart is that the books are not forgotten when a spin ends. Each one is added to a running count, so even spins with only one or two books move you closer to the free spins.
The 99-book collection
The meter is the reason for the name. Every book you land while playing the base game is added to it, and when the count reaches 99 the game awards 10 free spins, exactly as three scattered books would. That gives the feature two separate routes in: the usual scatter trigger on a single spin, and a slower one built up over many spins. Either way, the round that follows is the same, with 10 spins and an expanding symbol.
Free spins and the expanding symbol
Before the round starts, one regular symbol is drawn at random to become the special expanding symbol for those spins. Whenever it lands, it stretches to fill its whole reel, and those expanded reels pay together whether or not they sit on a particular payline. The round lasts 10 spins whichever way it was reached, by three or more books on one spin or by the 99-book count built up in the base game.
Book of 99 compared with Book of Dead
The obvious reference point is Book of Dead, released in January 2016 on the same 5x3 grid with 10 paylines. Its free spins work in much the same way: three books for 10 spins and a single expanding symbol drawn at random before they begin. The difference is how you get there. Book of Dead has one route, three or more books on one spin, while Book of 99 adds its collection meter, so books from earlier spins can still pay off later.
| Game | Released | Grid and lines | Route into free spins |
|---|---|---|---|
| Book of Dead | 14 January 2016 | 5x3, 10 paylines | Three or more books on one spin |
| Book of 99 | 4 May 2021 | 5x3, 10 paylines | Three or more books on one spin, or 99 books collected in the base game |
All values (Bet Levels, Maximum Wins etc.) mentioned in relation to this slot game are subject to change at any time.
Similar games you can play at Fortune Games
For another take on the randomly chosen expanding symbol, Legacy of Dead uses a tomb as its wild and scatter and picks a special expanding symbol at random for its free spins. Book of Shadows keeps the book as wild and scatter and also draws a Golden symbol at random to expand, with one chance to redraw it if you would prefer a different symbol. Both are in the Fortune Games lobby. Fortune Games has an app on the App Store and Google Play.
Frequently asked questions
How does the 99-book collection work in Book of 99?
Each book symbol that lands during the base game adds one to a running count. The count builds across spins rather than resetting each time, and at 99 books the game opens 10 free spins. It runs alongside the normal trigger, so three books on a single spin still start the round straight away.
Which symbol expands in the Book of 99 free spins?
There is no fixed one. Just before the round, the game picks one symbol at random to act as the special expanding symbol. Whenever it appears during the free spins it grows to cover its reel, and expanded reels pay together without needing to line up on a set payline.
What are the symbols in Book of 99?
The low-paying symbols are the card royals A, K, Q, J and 10. Above them sit the heroes and villains from Greek myth that give the game its setting, and the top character pays the most of any regular symbol, with its value shown in the key facts. The book stands apart from both groups, working as the wild and as the scatter that opens the free spins.
Related guides
- Book of Oz slot
- Rise of Olympus slot
- Greek mythology slots
- Free spins rounds explained
- More real money slots
Checked on 10 November 2026 against Relax Gaming’s Book of 99 launch release as published by Gaming Intelligence, the OLBG, Casinos.com and PokerListings records of Book of 99, Play’n GO’s game pages and the OLBG records for Book of Dead and Legacy of Dead, Nolimit City’s Book of Shadows page and its OLBG record, and the Gambling Commission’s stake-limit guidance. How we research and check our guides: our editorial policy.