Book of 99 – the Slot with a Record-Breaking 99% RTP: Is It Really the Most Profitable Game?
When discussing slot machines with high returns, Book of 99 by Relax Gaming often tops the list. With a theoretical Return to Player (RTP) of 99%, it challenges industry standards and appeals to players seeking mathematically advantageous games. But does this impressive figure make it the most profitable choice in reality? This article takes a detailed, unbiased look at Book of 99, separating marketing from math.
What Sets Book of 99 Apart from Other Slots
Book of 99 boasts an RTP that far exceeds the industry average, which typically sits around 96%. This means that, in theory, players receive €99 for every €100 wagered over the long term. However, such statistics only reflect large-scale performance and don’t guarantee outcomes in short sessions.
The slot’s core appeal lies in its simple structure and high-potential bonus round. The game features expanding symbols during free spins—a mechanism similar to other popular “Book of”-style slots. But its RTP is what gives it a distinct identity, especially among informed players.
Importantly, Book of 99 includes a feature allowing players to unlock free spins by collecting 99 books. This collection mechanic offers a clear, visible path to bonus activation, which enhances engagement and creates a sense of progression often absent in high-volatility games.
The Role of RTP in Long-Term Profitability
While 99% RTP is indeed exceptional, it’s crucial to remember that RTP is a long-term statistical measure. A single play session may deviate greatly from the expected value due to the variance built into the game. In Book of 99, high volatility means large wins are rare but potentially substantial.
That makes this slot better suited to players who can afford extended play or are willing to chase bonus rounds strategically. Over short sessions, the high RTP may not yield visible benefits, but across hundreds of spins, it significantly increases the potential for a better return.
In contrast, lower-RTP slots with frequent small wins may feel more rewarding in the short term but tend to erode player balance over time. Book of 99 flips this experience by focusing on statistical value rather than frequent gratification.
Gameplay Mechanics and Player Experience
The game offers a 5×3 reel structure with 10 paylines, maintaining simplicity that appeals to fans of classic slot design. Symbols include traditional card values and mythological characters, with the Book serving both as Wild and Scatter.
Visually, Book of 99 is well-designed but avoids unnecessary gimmicks. Its animation and soundtrack are understated, focusing instead on mechanics and RTP as the main draws. This reflects a deliberate design choice targeted at experienced players who prioritise value over aesthetics.
The expanding symbol feature in free spins is a hallmark of the genre, yet Book of 99 enhances it with its bonus meter. This persistent progression feature adds a semi-predictable element to gameplay, giving users a reason to stick with the slot longer than they might otherwise.
Volatility and Strategic Play
Despite its high RTP, Book of 99 is classified as a high-volatility game. This means that wins can be infrequent, but potentially large when they occur. For players, this volatility presents both risk and opportunity.
Those with smaller bankrolls should consider betting conservatively to prolong their sessions and reach the 99-book threshold, which activates the free spins. This approach gives them the best chance to take full advantage of the game’s structure and high theoretical return.
Ultimately, the slot rewards patience and discipline, especially for users who understand variance. It is not an ideal game for quick sessions or casual spins, but rather a value-oriented choice for players who prioritise long-term performance.
Book of 99 Compared to Other High-RTP Slots
Few modern video slots exceed an RTP of 98%. Among those that come close are titles like Mega Joker by NetEnt (up to 99%), 1429 Uncharted Seas by Thunderkick (98.6%), and Blood Suckers (98%). Still, most of these are either classic-themed or lack the bonus structure seen in Book of 99.
Book of 99’s unique combination of a high RTP, collect-to-trigger bonus feature, and dynamic free spins mechanism sets it apart. It strikes a balance between traditional “Book of”-style slots and statistical advantage, something that’s rare in the current catalogue of games.
Compared to these titles, Book of 99 offers a more modern, strategic experience while maintaining an edge for players interested in RTP-focused decision-making. This makes it a standout for users seeking both high value and engaging gameplay.
Is It the Most Profitable Game?
Profitability in slots depends on how one defines it. If viewed purely through the lens of RTP, then yes—Book of 99 ranks at the top. But profitability also involves session length, variance tolerance, and user discipline. The slot is not designed to deliver frequent small wins but instead targets a longer arc of returns.
That means it’s not for everyone. Casual players seeking quick, frequent wins may find it frustrating. However, for those who understand bankroll management and the mathematics of RTP, Book of 99 can be an excellent long-term choice.
In short, Book of 99 is among the most value-driven titles available, but its full potential only reveals itself when played with the right mindset and strategy.