Book of 99 Slot Review & Free Demo Play

The Book of 99 is an online slot from Relax Gaming, inspired by Greek motifs. It invites UK players on a journey to Ithaca, where the “Book of” theme blends with the collection meter mechanic, securing you a path to the bonus round. Record-shattering 99% RTP makes this slot a standout of its type. Hit frequency of 29.83% may also look outstanding, but volatility is still high, where sudden spikes of fortune intertwine with long dry spells.

We suggest loading the Book of 99 demo: test the progressive mechanics and gameplay in a free-play session.

About Book of 99

Relax Gaming added this video slot to its portfolio on May 4, 2021. The book's theme is far from new to the UK gaming market. We’ve already seen Book of Ra by Novomatic and Book of Dead by Play’n GO. Still, the top graphic artwork, progression system and the fact that it follows Homer's Odyssey narrative rather than Ancient Egypt give the RG’s game a unique identity.

Book of 99 features just 3 reels and 3 rows, plus each spin can potentially produce rewards on 10 fixed paylines.

Also, punters will encounter a set of symbols, covering the traditional low-paying royals and the main (thus the most rewarding) characters. We haven’t noticed anything special about the payout mechanics: prize combinations of at least 2 (or 3 for A, J and other basic symbols) occurrences on 10 fixed paylines. As always, the biggest potential is hidden within the extra spins bonus.

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Book of 99 Slot – Key Stats

• Volatility. It has a high-variance game, so paying combos appear less frequently – be ready for sustained cold streaks.
• Max win. This release offers a chance to multiply the stake by up to 12,075x, which is rather a good value, with an average potential of around 5,000x.
• Return to Player (RTP). Book of 99 RTP is 99% – it surpasses the average market boundary of 96%. Most releases we’ve reviewed sit at lower scores: Sugar Rush (96.5%), Koi Princess (96.23%), Legacy of Dead (96.58%). So the title we examine in this review delivers the best statistical value for your money.
• Hit frequency. The estimated win rate is 29.83%, a significant value for volatile slots – such usually feature it at 20%-25%.
• Betting range. The lowest bet size is £0.01, while the cap depends on the UK player’s age: £2 is the maximum allowed for under-25s. Punters over 25 can count on the £5 upper limit.

Bonus Rounds – What to Expect?

Relax Gaming loves dropping titles where extra rounds feel like a separate quest. Look at, say, Money Train release, which feels more like a video game, not an online slot machine. While the dramatic intro trailer to Book of 99 looks promising, this is not exactly the case. Here, you only get a classic free spins loop, which can be triggered in two different ways:

• Scatter trigger. If three golden books land before the counter reaches 99, you get free games instantly, without waiting. During the feature, we noticed that wins occur roughly 50/50, or slightly more often. It’s an incredibly good rate for the high-variance slot. Overall, almost every second swirl either returns your stake or produces a bigger payout.
• Collection meter. Every Tome symbol that lands on the reels adds 1 point to the meter. It acts like a tailwind in the player’s sails. Once you collect all ninety-nine items, the free spins round is triggered automatically. An expanding symbol is chosen at random, and the extra game begins. If three books appear again during the bonus, they will award an additional 10 plays.

Oksana Kumetska

Lead iGaming Expert at Cardmates

I personally tested the gameplay of Book of 99. For me, the collection meter and retriggering mechanics raise the bar for this slot, making the experience and the special phase more enjoyable and rewarding for the user. 

During my session, I quickly realised that hitting three Scatters is a rare event. And this is where you’ll see the title’s high variance in full swing. But when luck smiles on you, there’s a chance to retrigger FS three more times – I ended up with 40 spins instead of the original 10. I absolutely loved this potential.

Book of 99 Slot Real Experience  

We ran a 150-spin session to stress-test this Ancient Greek slot under realistic conditions. See the key details below:

• Duration: around 20 minutes.
• Stakes: £0.01, £1, £2.
• Starting budget: £100.
• Total winnings: £63.
• Net loss: £37.
• Top payout (base game): £9.

Take a look at some facts and hands-on experience gathered while we were preparing this Book of 99 slot review.

The actual volatility level matches the provider’s rating. The base stage wins occur at times, but they can quietly drain your balance if no FS trigger for a long time. Books drop on the reels as befits the risk level – far less frequently than you’d like them to show up. Hitting a 12,075x prize cap without entering the bonus round is a pipe dream. The maximum you can count on in the base phase is 500x for the five highest-valued symbols.

While playing at £1 and £2 stakes, most rewards covered our expenses, and mega wins during free games often pushed the balance into profit. The biggest losses hit us when paying £0.01 per attempt – 13-15 spins in a row were empty. And such streaks happened three times during the test session. Bad luck, probably. 

How much can you really win in the Book of 99 slot with different bets?

* Data in the table is provided based on our testing. Your experience and results may differ.

Bonuses We’ve Tried

Our first 50-spin session was a total failure: we landed no extra round. After 50 more turns, the first two sets of three books were on our record. During the next 50 attempts, we grinded through the base mode until we had grabbed three Scatters and gathered a total of ninety-nine elements. 

Subjective impression: the bigger the bet, the more stingy the Book of 99 becomes with free games. Nevertheless, we reached Ithaca only once in 150 spins across different stakes and caught 3 Scatters along the way.

Our Take on the Book of 99

Things we liked:

• The slot may return 99% in the long run – a huge rarity in the industry.
• The visual collection meter shows how far you are from 10 FS.
• Wins in the FS mode are genuinely valuable.
• Bonus rounds have expanding symbols, standard to the “Book of” genre.
• It’s easy to retrigger an extra 10 spins during the main reward game.
• At medium stakes, it’s possible to maintain a player-friendly balance for a long time.

Things we didn’t like:

• Playing with a £5 bet drains the bankroll too quickly due to high variance.
• 10 FS are the only bonus feature.
• The maximum prize cap of 5,000x is fairly low.

Oksana Kumetska

Lead iGaming Expert at Cardmates

Who is the Book of 99 slot for?

This title will satisfy casual punters who are ready to grind the base game and aren’t afraid of repetitive experiences. Enthusiasts who love Ancient Greek will also enjoy this epic mythological quest to grab 99 scripts. So will do the fans of progressive mechanics – the collection meter brightens up the action.

Once again, the Book of 99 game comes with high volatility, which can quickly drain your bankroll. If you’re not ready for such a level of risk, this title is the one to skip. As there are no other features except for bonus spins, the action will be boring for users who pursue the level of excitement the King Kong Cash slot machine delivers with its multiple special features.

Where to Play Book of 99 for Real Money

Our Honest Verdict

Relax Gaming’s Book of 99 burst into the genre with a jaw-dropping 99% RTP and a guaranteed path to the bonus round. Rather than forcing players to rely on luck in hitting 3 Scatters, the release focuses on a progression system – a safety net for punters.​

UK gamblers who focus on RTP percentages and look for slots with the highest values possible will absolutely love this release. If you’re a fan of the classic staples of the “Book of” genre, the upgraded game with accumulation mechanics is also a killer choice.

Well, this is not the title where you should expect fairy-tale payouts. With the top win ceiling of 5,000x, the Book of 99 slot sits on the medium level, especially if compared to the 30,338x that the giants like the Book of Shadows have. The attempts to collect 99 scriptures may feel repetitive and dull to thrill-seekers who love explosive bursts of cascades and flashy animations.

FAQ

⚙️ What is the core mechanic in Book of 99?

The core mechanic centres on forming combos of 2+ character symbols and 3+ low-value elements on any of 10 fixed paylines. Along the way, a Collection Meter grabs every tome that appears, adding 1 point to the progression bar, where gathering 99 means getting 10 FS. Or, users can get free games when 3 Scatters drop on the grid. 

📉 How volatile is the Book of 99 slot?

The title features high volatility. It means that many rounds may pass without wins, or you may get minor payouts for landing combos from time to time. It sometimes takes 100-150 attempts to enter the extra spins mode that can deliver valuable payouts.

🎁 Does Book of 99 offer a free spins round?

Yes, players can trigger free games either by gathering 99 books over the journey or by landing three Scatters at once, regardless of their position on the grid. The feature starts with 10 FS, and if three tomes appear again during the round, an additional 10 FS are added to the counter.