Book of 99
Greek Mythology Book slot with an alternative collection trigger
Only 0.02% of slots feature High Rtp Slots.
The SlotRanker Score is calculated from the visible data below. It is not affected by affiliate deals, and it cannot be bought.
Why this score
High confidence (100%)Five weighted signals shape the composite. Four context signals refine ties. See how we rate for the full methodology.
Popularity blends real player search demand (~30 markets) with a catalogue-derived proxy; games without measurable search demand use the proxy alone. Not live play telemetry.
SlotRanker Score: 80 — Book of 99 by Relax Gaming
https://slotranker.com/relax-gaming/book-of-99#scoreSlot Summary
How It Plays
Each base-game spin uses 10 paylines across the 5x3 layout. The Book serves as the key special symbol while also advancing the separate collection route.
The collection counter creates a second source of anticipation between Scatter hits. Reaching 99 Books moves play directly into the same 10-spin feature.
Theme & Atmosphere
The Ancient Greece setting casts the Book formula as an Action & Adventure encounter among mythic figures rather than a tomb-exploration story.
Mythology supplies the characters and scale, while the Book remains the visual and mechanical link between the base game and its special round.
Features & Win Potential
The Wild Symbol substitutes in regular combinations, while the Scatter Symbol controls immediate access to Free Spins and can also award a retrigger.
Stacked Symbols and Expanding Symbols concentrate full-reel potential inside the special round. The separate Symbols collection feature provides another route into that round.
Bonus & Free Spins
Free Spins begin with 10 rounds after either qualifying trigger. A randomly selected regular symbol gains the ability to expand across an entire reel.
Landing 3 or more Book symbols during the feature awards another 10 Free Spins, extending the opportunity for the chosen symbol to expand.
This game is searched most in Brazil, United Kingdom, and United States.
True Cost to Play
Expected average based on this slot's 99% RTP — individual sessions vary with volatility.
Estimate only, for entertainment purposes — treat gambling as entertainment, not a way to make money, and set a budget you can afford to lose.
Bankroll survival simulator
No matching casinos for your region yet
Casino availability depends on where you play from. We only show casinos that accept players from your country.
Compare Book of 99 with other games
 Book of 99 Score 80This game |  Pandora’s Treasure Score 75 |  Book of Helios Score 67 |  Book of Trojan Tales Score 56 |  Serpentina Score 91 | |
|---|---|---|---|---|---|
| Identity | |||||
| Studio | |||||
| Released | 5/4/2021 | 5/2/2024 | 6/16/2022 | 6/17/2024 | 3/20/2025 |
| Math | |||||
| RTP | 99% | 96.13% | 95.58% | — | 96.53% |
| Volatility | High volatility | Medium volatility | High volatility | — | High volatility |
| Max win | 12,075× | 10,368× | 20,168× | 5,000× | 30,000× |
| Format | |||||
| Reels | 5 | 6 | 5 | 5 | 7 |
| Layout | 5x3 | 6x4 | 5x3 | 5x3 | 7x7 |
| Paylines | 10 | 4096 | 10 | 10 | — |
| Min bet | 0.1 | 0.1 | 0.1 | 0.1 | 0.1 |
| Max bet | 100 | 40 | 10 | 100 | 100 |
| Features | |||||
| Progressive | — | — | — | — | — |
| Wild symbol | ✓ | — | ✓ | ✓ | ✓ |
| Free spins | ✓ | ✓ | ✓ | ✓ | ✓ |
| Scatter symbol | ✓ | ✓ | ✓ | ✓ | ✓ |
| Multiplier | — | — | ✓ | — | ✓ |
| Bonus game | — | — | — | — | — |
| Respins | — | — | — | — | — |
Every number is shown as a delta against Book of 99.
Explore More Games with Similar RTP
| Game | Provider | RTP | Volatility | Max win | Score | |
|---|---|---|---|---|---|---|
 | Ace Race (Jackpot Originals) | 98.75% | Adjusted | — | 60 | |
 | Golf 2 | 98.76% | — | 4,500× | 72 | |
 | Thrones of Persia | 98.83% | High volatility | 5,470× | 79 | |
 | Car X | 98.9% | — | 25,000× | 68 | |
 | World Champion X | 98.94% | — | 25,000× | 65 | |
 | Book of 99 | 99% | High volatility | 12,075× | 80 | |
 | Bear Smash: 15000X Boost | 99% | High volatility | 15,000× | 84 | |
 | Fairy Dust Xtreme! | 99.04% | Low/Medium | — | 65 | |
 | Diamond Trader | 99.07% | Low volatility | 3,000× | 55 | |
 | Fruity Beats Xtreme | 99.08% | Medium volatility | — | 62 | |
 | Chef Lady | 99.29% | — | 250× | 71 |
- Ace Race (Jackpot Originals)Jackpot OriginalsRTP98.75%VolatilityAdjustedMax win—Score60
- Golf 2Dragoon SoftRTP98.76%Volatility—Max win4,500×Score72
- Thrones of PersiaTom Horn GamingRTP98.83%VolatilityHigh volatilityMax win5,470×Score79
- Car XSmartsoft GamingRTP98.9%Volatility—Max win25,000×Score68
- World Champion XSmartsoft GamingRTP98.94%Volatility—Max win25,000×Score65
- Book of 99Relax GamingThis gameRTP99%VolatilityHigh volatilityMax win12,075×Score80
- Bear Smash: 15000X BoostCroco GamingRTP99%VolatilityHigh volatilityMax win15,000×Score84
- Fairy Dust Xtreme!SpinmaticRTP99.04%VolatilityLow/MediumMax win—Score65
- Diamond TraderBuck Stakes EntertainmentRTP99.07%VolatilityLow volatilityMax win3,000×Score55
- Fruity Beats XtremeSpinmaticRTP99.08%VolatilityMedium volatilityMax win—Score62
- Chef LadyDragoon SoftRTP99.29%Volatility—Max win250×Score71
Questions & Answers
Book of 99 FAQ
Book of 99 has a stated RTP of 99% and a high-volatility profile.
Land 3 Book symbols in one spin or collect 99 Books across base-game play.
Completing the Book collection awards 10 Free Spins, matching the round reached through the Scatter trigger.
One regular symbol is selected before the round and can expand to cover entire reels.
Similar Slots
Games like Book of 99 from other studios — same game type, matched by shared themes and features, then ranked by Slot Score.
