Book of Dead

Book of Dead was released by Play’n GO in January 2016 and is still, a decade later, the game most people mean when they say “book slot”. Five reels, three rows, ten adjustable paylines, an Egyptian tomb, and a single feature that the entire game is built around. Nothing about it is modern, and that is precisely why it survived.

The structure is simple enough to describe in one sentence: the golden book is both wild and scatter, three of them anywhere award ten free spins, and before those spins begin the game picks one ordinary symbol at random and promotes it. Whenever the promoted symbol lands during the round it expands to fill its whole reel and pays regardless of adjacency.

Maximum win is 5,000x the stake and volatility is high. Stakes start at 0.01 per line.

The RTP Question

This is the most important thing to know about Book of Dead, more important than any feature, and it is why our specification table shows 94.25% rather than the 96.21% quoted in most reviews.

Play’n GO supplies this game in a ladder of builds, and the spread is unusually wide:

The difference between the top and bottom of that ladder is not a rounding detail: the house edge quadruples. The same artwork, the same features, the same expanding symbol – and four times the cost per unit staked. Two casinos can both offer “Book of Dead” and be selling very different products.

Nothing on the game screen announces which version you have been given. The figure appears in the game’s own information or rules panel, and on a title with this spread it is worth opening every time you play it somewhere new. If a casino runs the 84.18% build, no strategy, stake size or session length compensates.

Book of Dead Features

The Book: Wild and Scatter

One symbol does both jobs. As a wild it substitutes for everything; as a scatter it pays from anywhere and three of them trigger the feature. Because it never needs to land on a payline to count, the trigger frequency is higher than a ten-line slot would otherwise suggest.

Expanding Symbol

Before the free spins start, the game selects one of the regular symbols. During the round, that symbol expands across its entire reel whenever it appears, and pays without needing to be adjacent to anything. Draw a high-value symbol and the round can be substantial; draw one of the card ranks and it usually is not. You have no influence over the draw.

Free Spins and Retriggers

Three books award ten spins. Landing three more during the round retriggers it with a fresh expanding symbol selection. Retriggers are where the largest results come from, and they are also the reason two sessions with identical trigger counts can end nowhere near each other.

Gamble

After a win the game offers a card-colour double-or-nothing. It does not change the expected return of the game; it only widens the distribution of a session. It is the oldest mechanic in the slot and the least consequential.

What the Numbers Say

5,000x is a modest ceiling by 2026 standards – most of the games on this site cap several times higher. On a game this old that is a fair trade: a lower ceiling with a decent build means more of the return sits in outcomes you will see rather than in a tail you will not.

The real variable here is not the ceiling but which build you are playing. A 96.21% Book of Dead and an 84.18% Book of Dead are, in expectation, entirely different games, and the difference between them dwarfs anything the expanding symbol can do for you.

Mobile Play and Demo

Runs in the browser on any device, no app. The 5×3 grid with ten lines is as readable as slots get on a phone, and the game is light enough to load on a poor connection – one of the reasons it is still stocked almost everywhere. The demo will show you the feature quickly, but it will not tell you which RTP build a given casino runs; only the rules panel on the real-money version does that.

Summary

A genuinely important slot, and one that ages well because it never depended on novelty. The mechanic is clean, the trigger is frequent enough to keep a session alive, and the ceiling is honest about itself.

The caveat is the RTP ladder. More than any other title on this site, Book of Dead rewards checking the information panel before you play – the same game can be reasonable or ruinous depending on a number the lobby does not show you.

More from this studio on the Play’n GO page, and the full catalogue in Casino Games.

Related Slots

• The Dog House – the same era and the same fixed-payline logic, with sticky multiplier wilds instead of an expanding symbol.
• Le Bandit – the modern alternative: cluster pays, a levelled bonus and a 10,000x ceiling.
• Gates of Olympus – where the industry went after book slots: no lines, no wilds, everything in tumbles.