Land the Books
Three or more Book wilds anywhere in one base-game spin start ten Free Spins at the triggering stake.
Read the full feature →
Independent player guide · fact-checked 22 July 2026
Book of 99
A rare 99% RTP slot with two doors into the same expanding-symbol Free Spins feature: land three Books now, or collect your way to ninety-nine.
18+ · Fun-mode demo · Partner access is clearly labelled
Collection route0—99Every base-game Book advances the meter
Enter the archive ↓01 · RTP99.00%
02 · Maximum win5,000×
03 · Reels5 × 3
04 · Paylines10
05 · Bet range€0.10–€100
06 · Released4 May 2021
I
the number that changes the proposition99% theoretical RTP
Why players still search for this book
A Book slot built around a number, not just a theme.
Book of 99 keeps the familiar 5×3, ten-line rhythm, but adds a visible long-form collection. Each Book wild in the main game moves a separate meter one step. Fill it, and the game awards ten Free Spins using an average based on the stakes that built the meter.
The headline 99.00% RTP is exceptional by slot standards. It is still a statistical average across a huge volume of play—short sessions can finish anywhere.
VerifiedGame figures checked against the Relax Gaming page and the live in-game help.
Two feature entries
One chamber. Two ways in.
Both routes lead to ten Free Spins and a randomly selected expanding symbol, but the stake used by the feature is not calculated the same way.
Complete the collection
Every main-game Book adds one. At 99, ten Free Spins begin at a weighted average of the stakes used while collecting.
Understand the average →
Real fun mode
Open the book before you risk a balance.
Explore the actual five-reel interface, meter and paytable through Relax Gaming’s fun-mode game. No imitation controls and no invented results.
Fun mode
The long route
Build a 99-Book session ledger.
Change the stake, add collected Books and watch the feature stake update. This is arithmetic from the published rule—not a result predictor.
Collection planner
Your road to 99
27/ 99 Books
Books remaining72
Current weighted average€0.37
Feature stateCollecting
When the meter triggers Free Spins, the feature stake is based on the weighted average of the stakes used to collect those Books. The game may round a non-standard average to an available bet step.
The payoff mechanic
See how expansion changes the screen.
A selected high symbol needs at least two instances; a low symbol needs at least three. Once qualified, reels containing it expand and can pay across all ten lines.
Expanding symbol lab
Build a feature screen
Tap the grid to place the selected special symbol. This visual explains the expansion rule; it does not reproduce game odds or outcomes.
3 symbols placed3 reels expand
V
Read the screen
Five reels, ten fixed lines, one persistent left rail.
- Reel window. Wins are evaluated left to right on ten always-active paylines.
- Book wild. It substitutes for every regular symbol and also drives both Free Spins entry routes.
- Collection rail. Base-game Books move the count toward 99; the rail survives between paid spins in the game session.
- Feature choice. The game—not the player—selects one regular symbol to expand for the Free Spins round.
Know what landed
The paytable, without the guesswork.
The top hero pays the most in the supplied €2 help view; A and K lead the low symbols. The Book has no ordinary line value—it is the wild and feature trigger.
Top displayed award1,000five Hero symbols · help screen shown at €2 current bet
Only the highest-paying combination on each line is paid. Wins across different paylines add together.
Open the complete paytable →The original release
Relax Gaming rewrote the Book format in May 2021.
Released on 4 May 2021, Book of 99 paired the familiar expanding-symbol setup with a standout return figure and a second, visible feature route. That combination—not mythology alone—is why the title still has a distinct search identity.
Player questions
Before you open the book.
01What is the RTP of Book of 99?+
The published theoretical RTP is 99.00%. It is a long-run mathematical figure, not a promise for a session.
02How do Free Spins start?+
Ten Free Spins are awarded by landing three or more Book wilds, or by filling the separate collection meter with 99 Book wilds from the base game.
03What happens in Free Spins?+
One regular symbol is chosen for the feature. When enough of that symbol lands, every reel containing it expands and can pay across all ten lines, even without the usual left-to-right connection.
04Is the Book of 99 demo real?+
Yes. The demo on this guide loads Relax Gaming’s official fun-mode launcher. It uses no real balance and may be unavailable in some locations.
05Can the 99 meter predict when I will win?+
No. It records collected Book wilds and provides a separate route into Free Spins. It does not predict spin results or guarantee profit.
Choose your next page
Study the feature. Try the real demo. Then decide.
Book of 99 is a game of chance. Its 99% RTP is meaningful over the long run, but no meter, symbol or session plan can make a random spin predictable.