Book symbol slot machines

What the book symbol does in a slot machine

A book symbol combines two special roles. In the base game it acts as a wild, standing in for other symbols to complete paylines. It is also a scatter: land three or more anywhere in view and the game awards free spins, plus a scatter payment on many games. A few book slots also pay the book on its own as a high-value symbol.

The format is so recognisable that it has become a category of its own. Our guide to book slot machines covers the type as a whole; this page focuses on the symbol and the expanding feature it opens. The slot machine symbols hub places it alongside the older traditional icons.

The book symbol’s jobs at a glance

Rules differ between games. Some newer book slots split the roles, use more than one expanding symbol or add extra modifiers. The help screen is the final word.

How the expanding symbol works in a book symbol slot machine

The feature that made book slots famous is the expanding symbol. When free spins start, the game picks one ordinary paying symbol at random. For the rest of the feature, whenever that symbol lands on enough reels to form a win, it grows to cover each of those reels completely and then pays.

1. Three or more books land anywhere and trigger the free spins.
2. The game reveals one randomly chosen special symbol for the feature.
3. Each free spin plays out normally, with ordinary line wins paid first.
4. If the special symbol appears on enough reels for a win, it expands to fill those reels.
5. The expanded symbols are then paid across all active lines.
6. Three or more books during the feature can add more free spins.

In Book of Dead and similar games, the expanded symbol pays on all ten lines even when the reels it covers are not next to each other, so a special symbol on reels 1, 3 and 5 can still pay as three of a kind. That is the source of the format’s big wins, and it is why the choice of special symbol matters so much: a premium symbol expanding across five reels pays far more than a royal.

Worked example: an expanding symbol at a 20p stake

These pays are invented to show the method. Imagine a 10-line, 5×3 book slot played at 20p a spin, so 2p a line, and a special symbol that pays 10× the line bet for three of a kind, 100× for four and 1,000× for five.

Five full reels in this example pays 1,000 times the 20p stake. Real games cap the total: Book of Ra Deluxe and Book of Dead both publish a maximum win of 5,000 times the stake, which would be £1,000 at 20p, £10,000 at £2 and £25,000 at £5, the two online limits set out in the Gambling Commission’s online slots stake limit guidance (opens in a new tab) for players aged 18 to 24 and 25 and over. Those outcomes are extremely rare; our max win caps guide explains how caps are applied.

Book symbol slot machines compared

The figures below are published specifications. RTP can vary by casino where a game is supplied in more than one version, so always check the help screen.

Our individual pages take apart Book of Ra Deluxe, Book of Dead, Legacy of Dead, Book of Oz and Book of Shadows. The last uses an expandable grid of up to 5×5 and 20 lines, which is why its maximum is so much higher. Play’n GO’s Book of Dead features its recurring adventurer Rich Wilde; see our Play’n GO provider page.

Where the book symbol format came from

The book format is closely tied to Novomatic, the Austrian company founded by Johann Graf in 1980, according to Wikipedia’s Novomatic article (opens in a new tab). Book of Ra Deluxe is dated to 2008 in published game data. We have not found a reliable source for the release year of the original Book of Ra, so we do not give one here. Novomatic took a controlling stake in the London online studio Greentube in 2010, which brought its games online.

Play’n GO’s Book of Dead then made the format a staple of UK online casinos, and many studios followed with their own book games, often on Egyptian themes. Our Egyptian symbols page and the wider history of online slots put this in context.

Why book slots are so volatile

A book slot concentrates much of its return in the free spins, and much of the free spins’ value in one rare outcome: a premium symbol expanding across four or five reels. The base game, with its 10 lines, returns relatively little in between. That is the recipe for high volatility.

If you prefer steadier play, our page on low volatility slot machines lists the alternative profile.

UK rules that apply to book slots

UK versions of book slots follow the same online rules as every other slot. Since 31 October 2021 there has been no autoplay, a minimum of 2.5 seconds per spin and no slam-stop, and games must not celebrate returns that are no bigger than the stake. Slots supplied to UK-licensed casinos do not offer a feature buy, so the only way to reach the free spins is to land the books. The full wording is in the Gambling Commission’s responsible product design standard (opens in a new tab).

Older book games often included a gamble feature after wins; whether a UK version offers one depends on the game and the casino, so check the help screen. The hi-lo gamble page explains how such features affect your return.

Book symbol myths

Where to play book symbol slots

We cannot say which partner carries any book slot at a given time, so search each lobby; availability changes. Coral offers new players aged 18+ 100 free spins at 10p each on selected games after a deposit and £10 of slots bets, with no wagering on winnings, 48 hours to accept and 7 days to use them. Ladbrokes offers up to 500 no-wagering spins at 10p, 50 a day for 10 days, after a £10 slots spend.

PlayOJO’s 80 no-wagering spins, for a first deposit of £10 or more, are on Big Bass Bonanza rather than a book game. Free spin offers normally run on named games, which may not include book slots. Some payment methods are excluded, all offers are 18+ and terms apply.

18+. Gambling should be entertainment that costs money, not a way to make it. Decide a budget before you play: plan a slot budget. Free, confidential help: National Gambling Helpline 0808 8020 133.