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Book of 99 Slot: 99% RTP? Let’s See What’s Up

m.pemberton Updated: 23.04.2025 18:03

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Book of 99 Slot — Quick Take

Relax Gaming dropped a new slot, Book of 99, and it’s all Greek mythology vibes, Odyssey style. Think Homer, Trojan Horse, that whole saga. They’re using this classic story for a new «Book» series slot. Expect familiar mechanics but with a twist.

Book of 99 is a 5-reel, 3-row, 10-payline online slot. Bets go from a tiny 0.10 to a max of 100. But here’s the kicker: 99.00% RTP. Yes, you read that right. It’s high volatility, hit frequency around 29.83%, and you can max win at 12075x your stake.

Book slots, you know the drill — expanding symbols in free spins, triggered by 3+ Wilds. But they added a Collection feature: 99 Wilds collected also gets you into free spins. Features: Wilds, Free Spins, Expanding Symbols, Collection. Simple.

Book of 99 — The Details

Visually, it’s Ancient Greece. Golden Age buildings in the background, columns framing the reels. Odyssey characters on the symbols, music sets the mood. Works on mobile too, so you can chase those free spins on the go.

Low pays are your standard 10-A royals, blinged out with gems. Need 3+ in a row from the left to win. High pays are Odysseus, a purple hooded lady, Siren, and Cyclops. Regular 1×1 size, but expand to 1×3 in free spins to fill reels. 10 symbols total, Wild is, unsurprisingly, a book. Fewer symbols can mean more frequent wins. Let’s dig into the features.

Book of 99 Features Breakdown

Max Win on Book of 99?

12075x your bet is the top prize.

What Features Does Book of 99 Have?

Wilds, Free Spins, Expanding Symbols, Collection feature.

Wild Symbols

Wilds sub for other symbols to help you make lines. Also, they’re Scatters. Hit 3+ and you’re in the free spins.

Free Spins

Free spins are the main event. Trigger ’em ASAP. 3+ Wilds gets you 10 free spins. Re-trigger with 3+ Wilds during free spins for another 10.

Expanding Symbols

Before free spins start, a pay symbol is picked at random. When it lands in free spins, it expands to cover the reel. Expands don’t need to be adjacent to pay, which is nice.

Collection

Free spins are where it’s at. Trigger via 3+ Scatters or the Collection. Base game Wilds are collected. Get 99 Wilds, and you get free spins. Bet level for collection spins is an average of your bets while collecting those 99 Wilds.

F.A.Q.

What is Book of 99 and what is it about?

Book of 99 is a captivating online slot game developed by Relax Gaming, drawing its inspiration from the rich tapestry of Greek mythology, specifically the epic journey of the Odyssey. Imagine stepping into the world of Homer, the Trojan Horse, and the legendary saga itself – this slot game encapsulates that very essence. It joins the popular "Book" series slots, offering familiar mechanics that players have come to expect and enjoy, but with some exciting and innovative twists that set it apart from the rest. Prepare to be immersed in an ancient world filled with mythical characters and the potential for thrilling wins as you spin the reels of Book of 99.

What makes Book of 99 unique compared to other "Book" slots?

Book of 99 distinguishes itself from other slots in the "Book" series primarily through two exceptional features. Firstly, and most notably, it boasts an incredibly high Return to Player (RTP) rate of 99.00%. This is significantly higher than the average RTP found in most online slots, offering players a much more favorable theoretical return over time. Secondly, in addition to the traditional method of triggering free spins by landing Scatter symbols, Book of 99 introduces a unique Collection feature. This innovative mechanic allows players to collect Wild symbols during the base game. Once 99 Wild symbols have been accumulated, players are automatically awarded free spins. This dual approach to triggering the coveted free spins feature provides players with more opportunities and excitement in their gameplay, setting Book of 99 apart as a truly exceptional and player-centric slot game within the "Book" genre.

How do I trigger the Free Spins feature in Book of 99?

There are two exciting ways to trigger the Free Spins feature in Book of 99, giving you ample opportunities to reach this highly rewarding bonus round. The first, and perhaps more traditional method, is by landing 3 or more Wild symbols anywhere on the reels during a single spin in the base game. As the Wild symbol in Book of 99 is also the Scatter, landing three or more of these book symbols will immediately award you with 10 free spins. The second method, which is a unique and innovative addition to Book of 99, is through the Collection feature. Every Wild symbol that lands during the base game is collected. Once you accumulate a total of 99 Wild symbols, you will automatically trigger the Free Spins feature. This dual trigger system ensures that players have more chances to access the Free Spins and experience the game's full potential.

What happens during the Free Spins feature in Book of 99?

The Free Spins feature in Book of 99 is where the real magic happens and significant wins are possible. Upon triggering the Free Spins, either through landing 3+ Wilds or via the Collection feature, you are awarded 10 free spins. Before the free spins commence, the game randomly selects one of the regular pay symbols to become the special Expanding Symbol for the duration of the bonus round. Whenever this chosen symbol lands on the reels during a free spin, it will expand to cover the entire reel vertically, if doing so can create a winning combination. Crucially, these expanded symbols do not need to be on adjacent reels to award a win, greatly increasing your chances of hitting multiple paylines simultaneously. Furthermore, landing 3 or more Wild symbols during the Free Spins feature will re-trigger the bonus, awarding you another 10 free spins, potentially extending your winning streak and excitement.

What is the RTP and Volatility of Book of 99 and what does it mean for players?

Book of 99 boasts an exceptionally high Return to Player (RTP) of 99.00%. RTP is a theoretical percentage indicating the potential return to players over a long period of gameplay. An RTP of 99.00% is remarkably generous, suggesting that for every €100 wagered, theoretically, €99 could be returned to players in winnings over extended play. In addition to its high RTP, Book of 99 is classified as a high volatility slot. High volatility means that wins may not occur as frequently as in low or medium volatility slots, but when they do hit, they are likely to be of a larger size. The hit frequency is around 29.83%, meaning you can expect to see winning combinations land roughly once in every three spins. This combination of high RTP and high volatility makes Book of 99 an appealing choice for players who are seeking potentially significant payouts and are comfortable with periods of less frequent wins in anticipation of larger rewards.

Where can I play Book of 99?

Book of 99 is available to play at a variety of reputable online casinos and bookmakers. You can find this exciting slot game at platforms such as LeoVegas, Unibet, Casumo, Videoslots, and Betsson, among others. These are all well-established and trusted online gambling operators that offer a wide range of casino games, including slots from Relax Gaming, the developer of Book of 99. To start playing, simply visit the website of any of these listed bookmakers, search for "Book of 99" in their game library, and you will be able to launch the game and begin your adventure into the world of Greek mythology and potentially lucrative free spins. Ensure to check the specific availability of the game in your region and the terms and conditions of each platform before you start playing.

Experts

Malcolm Pemberton

A veteran casino correspondent from Bristol, Malcolm Pemberton has traveled to gambling hubs worldwide but maintains that British betting culture offers the richest stories. His weekly column dissecting new slot games combines wry humor with practical advice for players navigating the increasingly complex world of online casinos.

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