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Book of 99 Slot

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Book of 99 is a 10-payline online slot developed by Relax Gaming. Features included a bonus meter, symbol collection feature, expanding symbols and free spins. The RTP of this high vola...tility slot is 99% and its top prize is worth 12,075x.

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  • Two ways to trigger free spins
  • Classic book of bonus feature
  • RTP much higher than average


Relax Gaming brings players a more scaled-back experience in Book of 99 – but, there’s more than meets the eye in this 10-payline slot.

The game comes with a 99% RTP and allows players to trigger free spins (with the classic expanding symbols feature) in two ways.

Theme and Graphics

Book of 99 is a Greek mythology-themed slot from Relax Gaming.

The graphics are rendered in a unique comic book style that brings the legends of Greek myth to life in a new way.

Like all Relax Gaming slots, there really isn’t anything to complain about in terms of its design.

Watch out though, this game is volatile.

Book of 99 Slot

How to Play

The game controls for Book of 99 are pretty straightforward:

  1. Once the game loads, click on the three bars in the bottom right-hand corner of the screen. This will take you to view the paytable and in-depth rules.
  2. From this menu, you can also adjust audio settings.
  3. To adjust your wager, you can use this menu, or click on the coin symbol above the spin button. Wagers from £0.10 are available.
  4. Hit the spin button!

Book of 99 Free Spins

Book of 99 RTP and Variance

Relax Gaming’s Book of 99 brings players something we really haven’t seen before – an RTP of 99%. It’s very uncommon for an online slot to have an RTP of anything higher than 97%. Most games tend to fall between 96% and 96.5%. 

Book of 99 is also a highly volatile online slot game.

How to Win

There are 10 paylines in Book of 99, and wins are created by landing three or more matching symbols on any of them. The lower paying symbols are your typical poker ranks with payouts ranging from 0.5x to 15x your stake.

The higher paying symbols are various symbols from Greek mythology. These symbols all pay out of 2-of-a-kind combinations and above, which likely contributes to the high RTP of this slot.  

Max-win 12,075x
Volatility High
Top RTP 99%

Free Spins and Bonuses

When you land three book symbols on the reels, you’ll trigger the free spins round. During this bonus, one symbol is selected to be the expanding symbol.

When this symbol appears on the reels, it will always expand and pay as a scatter. This is the feature that you’ll find in most “book of” slot games, and it’s become hugely popular in the gaming market.

Disclaimer: Book of 99 trademark / license is owned by Relax Gaming. This site is not endorsed by Relax Gaming.

Slot Data
Slot Name: Book of 99
Software: Relax Gaming
RTP: 99%
Volatility: High volatility
Paylines: 10
Reels: 5
Min Bet (all lines covered): £0.10 (GBP)
Max Bet: £100 (GBP)
Top Win: 12075
Features: Wild Symbol, Scatter Symbol, Free Spins, High volatility, 5 Reels, Stacked Symbols, High Payout, High RTP Slots
UK Available in UK? Yes. Relax Gaming have a UKGC license and are allowed to offer their games at UK licensed casinos.

Book of 99 Slot FAQs

What is the RTP of Book of 99?

Book of 99 has a payout of 99%.

How volatile is Book of 99?

Book of 99 is a high volatility online slot with a top prize to match – 12,075x your stake.

How does the collection feature work in Book of 99?

Whenever you land a wild symbol, it will charge the collection meter. Once you’ve collected 99 symbols, you’ll trigger the free spins bonus.

Can you retrigger the free spins round in Book of 99?

No matter how you trigger the free spins bonus, it can be retrigger by landing three more scatters. You’ll get 10 more free spins each time you retrigger the bonus.

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