Book of 99 Online Slot

Published: May 11th, 2021 | Updated: Oct 26th, 2022
Published: May 11th, 2021 | Updated: Oct 26th, 2022
Game Provider
Maximum win
Progressive Jackpot
Bonus Feature
Ancient Greece, Myths and Legends
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Slot Setup and Betting Options

  • 5 Reels
  • 3 Rows
  • Autoplay Option
  • 3D Graphics
  • 05.04.2021 Release Date
  • Mobile Version
  • $0.10 Minimum Bet
  • $100.00 Maximum Bet
  • $0.01 Minimum Bet Line
  • $10.00 Maximum Bet Line
  • 10 Paylines
  • Win Both ways

Book of 99 Online Slot Review

There’s an incredible return to players percentage of 99% from the Book of 99 slots game. This PC and mobile slot comes from Relax Gaming and it’s themed around ancient Greek legends, with cartoon-style symbols of heroes, a cyclops, and harpy on the 5 reels.

You collect wild book symbols here, building a library of 99 books to trigger a free games round. You can also enter this feature with enough wilds in view, and during the games, it’s easier to win from a special expanding symbol.

The Book of 99 slots game has a high volatility, but it’s matched to a huge potential win of 12,070x your wager. The fantastic return to players percentage of 99% is almost unique.

How to Play the Book of 99 Slot Machine

Like many Greek-themed games, the reels of the Book of 99 slot are framed by the sturdy columns of a temple. A book collection meter snakes up one side, leading you along the path to that magical 99 level. The symbols include jeweled playing card icons, and four character symbols, which pay the higher prizes when crossing any of the 10 paylines.

It’s a good-looking game, with some nice animations from winning symbols, and you can enjoy it on PCs, Android, iOS, and Windows mobiles at the best Relax Gaming casinos.

You won’t have any trouble getting started, as it’s designed for ease of use. Click the coin buttons to select a wager from a range of 0.10 to 100.00 for each spin at one of our recommended Pennsylvania slots sites and the top New Jersey slots sites. The double arrow button activates a fast-play mode, and the circular arrows start the reels spinning on their own.

Press the 3 small lines on the controls, and you get through to a paytable, where you see how much each symbol is worth, and how the various features can land you with big wins. The heroic character pays from 1x to 500x your total wager, depending on how many reels on a payline he lands across.

Free Spins & Other Book of 99 Slot Features

The mysterious book is a wild symbol which has the power to act as any other if it’s seen in the right place to complete a win. Each time it appears, whether it helps to form a win or not, the book collection meter rises by 1. Once you build up to 99 books, you gain automatic entry to a free spins bonus round.

It’s not the only path to the bonus games, as any 3 books appearing in the same spin will also launch the round. Before the free games begin, the book opens to reveal a random symbol that will expand on any reel it lands on throughout the feature. It doesn’t even have to be on adjacent reels to pay out, which make it much easier to grab prizes from whichever symbol the book selects. Any 3 books landing in a free spin will retrigger the round.

Slot Features

  • Multipliers
  • Scatters
  • Wild symbol
  • Free Spins
  • Stacked symbols
  • Re-spins
  • Quickspin
  • Gamble feature
  • Retriggering

Maximum Wins, RTP, & Volatility of the Book of 99 Slot Machine

It’s possible to win a huge 12,070x your wager from the Book of 99 slot, which equals 1,207,000.00 at the maximum stake. In case we haven’t mentioned it once or twice, the average return to players percentage is 99%, which is incredible value and means that you can play for longer, with less risk. However, it’s a high volatility game, so be prepared to suffer a few losing spins in a row before grabbing a generous payout.

Our Book of 99 Slot Rating

You don’t have to be a fan of Greek-themed games to enjoy the Book of 99 slot machine. In some ways, it’s very similar to other ‘book’ slots, where the same symbol is both wild a scatter emblem, and a random symbol expands during the free games.

But the collection feature makes it easier to trigger the free spins in the first place and helps towards that amazing average return to players percentage. Open the Book of 99 online slot at the best Pennsylvania and the best New Jersey slots sites and be sure to claim their biggest and best welcome bonus deals.


Follow our guide to the best Relax Gaming online casinos. These sites all carry the Book of 99 slots game, along with the rest of this hugely popular range. You’ll find some great welcome bonuses at these fully licensed casinos, with excellent customer service as standard.

The return to players percentage of the Book of 99 is so good they named the game after it. As a long-term average, it pays back at a rate of 99%, or 99.00 for every 100.00 placed in wagers. That’s well above the usual figure for slot machines, which is normally between 95 – 97%.

The Book of 99 online slot has a high volatility. You could see the reels spin several times before you land a winning combination, but the flip side of this is that prizes tend to be relatively high value. Low variance slots work the other way and pay out smaller win with greater frequency.

Yes, you can. Like others in the Relax Gaming range, the Book of 99 online slot is fully optimized for iPhones, iPads, Windows, and Android mobiles and tablets. It has all of the same style, features, and payouts as the desktop version, so there’s no need to make any compromises.

This is a 10-line game. There are 10 different ways that you can line symbols up across the 5 reels of the Book of 99 slot for a win. At least 3 examples of the same symbol are needed on adjacent reels from the left side, and the longer the sequence, the higher the payout.

The book symbol has 2 important duties here. It’s the wild symbol of the Book of 99 slots game, so can step in when needed to complete a win. It’s also the scatter symbol and if 3 or more appear at once, they trigger a free games round. You also collect any book symbols, and once you have 99, the free games start.

The Book of 99 is a slot themed around ancient Greek legends. Cartoon-style symbols include a handsome hero, beautiful princess, cyclops, and a harpy. You’ll also discover playing card symbols in a Greek style and the mysterious yet powerful, book itself.

Casinos don’t normally have promotional codes for specific games, but occasionally, they run special offers that let you play a slot, such as the Book of 99, for free. We always publish the latest deals here at, so keep checking out our pages to make sure that you don’t miss the newest offers.

Similar games include The Hand of Midas, from Pragmatic Play. This game is also based on an ancient Greek legend, while the Divine Fortune online slot by NetEnt follows a similar topic and comes with a huge progressive jackpot prize.

The Book of 99 slot machine was launched on 4th May 2021.

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