Book of 99 Slot Review

(2 votes)
High RTP
Book of 99 Specification
Release May 2021
Provider Relax Gaming
Max. RTP 99%
Reels 5
Paylines/Ways 10
Betting Range (€/$) 0.10 - 100
Max. Payout 5,000x
Progressive Jackpot No
Megaways No

From time to time, new slot games come out while offering something unique, which will give them a big edge over the competition. It’s definitely the case with Book of 99, from Relax Gaming, whose biggest advantage in this market is the fact that it promises a 99% RTP. Story-wise, it’s a slot which has the legends of Ancient Greece as inspiration. It’s going to take quite a bit from the Book category, especially feature wise.

Book of 99 offers 5x3 reels, along with 10 lines which will be active each round. Wins of 5,000x the stake are not unheard of for this type of layout and features, but the 99% RTP is the one that will surprise. At the same time, it’s going to have high volatility, and a mix of special features which will give you Book wild/scatters, along with the usual free spins with expanding symbols.

Betting and Prizes

The total bet is the one that you get to work with. $0.10 is the lowest it can be, while $100 is the maximum bet.

When it comes to this sort of slot machine, with Book-style mechanics, a win of 5,000x the stake is pretty much the standard top payout. It’s what we get from Book of 99 as well.

It’s not going to be easy, as the volatility of the slot is expected to be high. Still, since they mention a 99% RTP for this game, I can’t help but feel some optimism. I’m sure it’s what it was designed for, and it’s only what’s calculated in a best case scenario, but that option is still there.

Book of 99 Slot Features

You can expect a fairly common mix of features in Book of 99. It’s a game which has a Book symbol, to be used as wild or scatter, depending on how many times it lands and on the other symbols present on its lines. As a substitute it is useful, but it’s even better if it lands at least 3 times at the same time, to get the free spins triggered.

As you’d expect, the Book selects a random symbol, to become special for the free spins. It will be able to expand on its reels, and it will have a much better chance of filling all lines with symbols, and get you a very good prize. These will even pay as scatters, so you just need them showing up on 3+ reels, for them to form combinations on all 10 lines.

One of the things which will make this slot interesting, is the collection of wild/scatter symbols along the way. This happens during paid spins, and as you collect wild symbols from the game’s spins, you can eventually trigger 10 free spins this way. You need 99 wilds collected though, before you can get into the free games, so it’s not an easy task.

Theme & Design

Stories which use Ancient Greece for influence are easy to find these days. You can get all sorts of symbols from those stories on the reels, including a male and a female, a Lamia, Cyclops, plus the less interesting Royals (10 to A). Overall, I wasn’t impressed with the graphics from Book of 99, though the top symbols were fairly well made. The story of this one was told many times before, in one form or another, and often the design was better.


Book of 99 has one huge advantage over any other online slots out there, and that’s the RTP of 99%, the highest rating that you will get from any such game. Regardless of how realistic that might be for individual players, there will always be enough of them willing to try it out, since it gives them the best odds.

Book of 99 Slot Machine FAQ

❓ What is a key options of the Book of 99 slot?

✔️ Slot developer: Relax Gaming , Max. RTP: 99% , 5 reels with 10 paylines , Betting Range (€/$): 0.10 - 100 , Max Payout: 5,000x .

❓ Where can I play Book of 99?

✔️ NewSlotGames team prepare a rating of online casinos with Relax Gaming games. Try top recomended licensed Relax Gaming casinos with Book of 99 slot.

❓ Can I play Book of 99 slot on my phone?

✔️ Yes, it's absolutely mobile-friendly!

❓ Where can I play this slot machine free?

✔️ You should choose one of the recomended online casinos listed here and push "Play Now" button. Any casinos ask you to register account, any casinos allow to play Book of 99 free without registration.