Book of 99 Slot Review

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95% Rated

Graphics - 90%

Gameplay - 97%

Bonuses - 92%

Value - 100%

Whizz hot?

  • 99% RTP
  • 12,075x top payout
  • Loyal players rewarded via Wild Collection
  • Free Spins with Expanding Symbols

Whats not so hot?

  • Traditional “Book of” formula not for everyone

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98% Rated


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97% Rated


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Game information


Book Of 99


Relax Gaming









Book of 99 is a Relax Gaming video slot with 5 reels, 3 rows, and 10 paylines. The theme of the slot is all about Greek mythology with heroes and monsters. That’s fine and the bonus rounds adhere to the “Book of” formula.

The hit frequency stands at a reasonable 29.83%, which is higher than most high variance slots. Moreover, winners come around every 3.3 spins. The max win reaches 12,075x and the volatility clocks a 10’er on the Whizz’s slots. Furthermore, Book of 99 sweetens the pot with Book Symbols, Free Spins, and Wild Collection Feature.

The betting range is wide from $0.10 to $100 per spin across all mobile devices. Speaking of a mobile slot; the game now features in the libraries at our top real money mobile casinos!

book of 99 slot by relax gaming

RTP & Symbols

The RTP of the payback rate of Book of 99 is unique. The industry average is 96%, but here the RTP is an amazing 99%! That sounds almost unreal and we had to check a few times when we first saw it on our screens. Needless to say, it’s the slots with the highest RTP for 2021. Two thumbs up from the Casinowhizz team to Relax Gaming. At least they weren’t playing Dota 2 when they designed the slot.

The payout system is classic. To receive a winning spin you need 3 or more matching symbols on the reels from left to right. The Greek theme comes with some nice symbols. For low pays, there are card ranks with gems inside.

The high-value symbols offer more bite and their visual stying is good. There are two heroes and two monsters. The first monster is Lamia and the other one is the Cyclops. The nice thing about the premium symbols is that they offer decent cash prizes. For example, 5 premiums on the reels will net you a payout of 500x.

Due to online gambling regulation in the States, Book of 99 is not available to U.S players. Real money slots players from North America can visit our best USA casinos online. Once you sign up they offer you a massive Bitcoin bonus to play slots like Betsoft’s, Mr. Macau.

book of 99 slot by relax gaming

Bonus Rounds

Book Symbols

The Book symbol serves as both the game’s Wild and its Scatter. It substitutes the other symbols and it triggers the Free Spins feature. There are no bonus coin wins for triggering it. It’s a tad disappointing as it deviates from the standard “Book of” slots norm.

Free Spins

Now, if you fancy your chances of winning the jackpot of more than 12,000x your stake. You must trigger the free spins feature. To do so, you need 3 or more Book symbols on the board and you’ll trigger the Free Spins Feature.

The online slot awards you 10 free spins and randomly chosen Expanding Symbols. They expand to cover entire reels and pay even if they’re not adjacent to each other. More importantly, when they pop the wins will be dandy. You can also re-trigger the Free Spins should 3 or more Book symbols pitch.

Wild Collection

For loyal players, the Wild Collection Feature will come in handy. As you play, you’ll collect all the Book symbols in a special meter. Collect 99 of them and you’ll trigger the Free Spins Feature in a different way. It works the same, well more or less. Furthermore, there are no compromises in terms of Expanding Symbols or anything like that!

book of 99 slot by relax gaming

Book of 99 Tips & Strategy

We played Book of 99 with a bankroll of $100 at an average bet of $2 per spin. This gave us 50 spins. Right off the bat, we received plenty of winning spins albeit small in the base game. We used the Auto Play feature and selected 25 spins for 2 sessions. The biggest win we got in the base game was $10.

The only downside for us was we didn’t catch any 99 Book symbols. We triggered the Free Spins Feature within 30 spins. Moreover, we managed a premium symbol as the Expanding Symbol. Massive wins ahoy and we walked away with a big payout, even though there were no retriggers.

The final screen showed a $72 win. Not bad for an investment of $100 for an overall profit of $40.



Book of 99 is one of the better Relax Gaming slots we played recently. We also commend the studio for rolling out a slot with an RTP of 99%. To be honest, it’s as scarce as picking up a diamond during your Sunday morning stroll.

Otherwise, it’s a classic “Book of” slot with the Wild Collection Feature. You’re also looking at payouts of 50x to 200x on average in the free spins. Which is vastly better than the free spins features of 99% of the slots out there.

Even if you don’t get lucky with the Book symbols, you’ll collect 99 if you play for long enough. Therefore, it’s safe to conclude that the slot’s longevity looks quite promising. Unlike the majority of the slots that burn you over the long haul. From our own playing experience, Book of 99 will reserve a special place in the hearts of slot players. With its massive jackpot and smashing RTP; Book of 99 sets the tone for other slots to follow.

If you’re into slot games with high RTPs and big jackpots, check out another Relax Gaming slot, Sails of Fortune.

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