TrueLab Games has never looked like a studio that wants to live off one template alone. Its catalogue jumps between classic fruit slots, experimental mechanics, rock themed volatility bombs and even instant games. Yet the Book series shows another side of the developer, one that understands how to work with a very familiar slot framework without turning it into a lazy copy of older hits. In the official catalogue, the line is represented by Book of Truth, Book of Huli and Book of Odin, and together they form a compact but quite telling trilogy of book-driven adventures.
What makes these games at Union Jackpots casino worth discussing is not just the word Book in the title. Plenty of developers slap a sacred tome on the reels and call it a day. TrueLab tries to give each entry a slightly different pulse. One leans into Egyptian secrecy and two-tier feature design, another pushes a fox-spirit myth with a second, stronger bonus state, and the most recent one goes Nordic while staying closer to the classic book-slot script. The family resemblance is obvious, but they are not dead clones. They are variations on the same ritual, each one shifting the mood and the bonus structure just enough to matter.
What defines the TrueLab Book series
At the core of the Book line sits a formula that slot players know very well. A special book symbol acts as a key object. It may substitute, scatter, or both. Free spins are central. Expanding symbols do the heavy lifting inside the feature. Variable paylines are used to control how broad or narrow the game feels. TrueLab keeps all of that, but tweaks the pressure points from game to game. That is why the line works better as a series than it might first appear.
Book of Truth uses two levels of free spins and builds towards a more extreme state where all symbols can expand. Book of Huli adds dual bonus rounds and makes the second one feel like a true escalation rather than a cosmetic extension. Book of Odin goes for cleaner Norse-flavoured execution, with a wild scatter, expanding symbol selection and a buy bonus path that makes the classic structure a bit more flexible. The result is a series that stays close to tradition while still showing signs of a modern studio trying to sharpen the old formula instead of just reheating it.
Book of Truth is still the deepest and most dramatic chapter
Released on 15 July 2021, Book of Truth is the oldest title in the line, but it still feels like the most layered one. The official page lists it as a modern slot with 1 to 10 paylines, RTP settings of 96.33 per cent, 94.01 per cent or 92.14 per cent depending on configuration, and a maximum win of x15000. The volatility is shown on the page as a mid-level meter rather than a written label, so the safest reading is that it sits in moderate territory with enough room for sharp swings once the stronger feature state arrives.
Its storyline leans into ancient Egypt and the old fantasy of forbidden knowledge turning into treasure. The Book of Truth is not just a decorative relic. The page presents it as a powerful luck amulet and a gateway to hidden wealth. That framing matters because this slot is built around revelation. It is not a charge-up machine like a Dr. Rock game and not a pure line-count classic either. It is about opening sealed doors and waiting for the book to show its real face inside the bonus.
Mechanically, the game follows the book tradition but with a bit more bite. The book substitutes for all symbols and also starts two kinds of free spins with expanding symbols. That already gives the slot a broader feature identity than the average single-stage book release. Three or four book symbols trigger the standard free spins, where a random expanding symbol is selected. That part is familiar and works exactly as it should. The expanding symbol can land during the feature and stretch to cover the reel, creating those chunky, old-school win shapes that make book slots so oddly satisfying.
The real edge comes from the stronger state called True Free Spins. According to the official description, this is where the ultimate secrets of the pharaohs are revealed and all symbols expand to cover the reels, opening the route to the x15000 ceiling. That extra layer gives Book of Truth a proper sense of progression. It does not simply hand out the usual bonus and stop there. It suggests that the first level is only part of the story and the full power of the book sits further inside. For a title from 2021, that structure still feels pretty sturdy. It adds tension without clutter, which is exactly what a good book slot should do.
Book of Huli adds a fox spirit twist and sharpens the bonus ladder
If the Book of Truth is the solemn keeper of old secrets, Book of Huli is the sly one. It was released on 12 January 2024 and the official page lists it as a modern slot with 1 to 10 paylines, RTP of 96.32 per cent and a maximum win of x15000. Its volatility meter sits a touch higher than the mid-point on the page, which suggests a somewhat firmer risk profile than Book of Truth, though the site again uses a visual scale rather than a plain-text category.
The game swaps pharaoh mysticism for a fox-spirit fantasy, and that shift works better than it sounds. The official description is brief, but it points to a benevolent white fox and a mystical book whose power can be progressively unleashed. That is enough to give the slot a distinct personality inside the Book line. It feels less like a tomb-raiding relic hunt and more like a half-sacred, half-trickster encounter where the bonus may open in stages rather than all at once.
This is where Book of Huli gets clever. The first bonus layer is straightforward enough. When three or four scatters appear, the white fox grants ten free spins with a special expanding symbol. That keeps the game connected to the classic book tradition. It knows the player expects expanding reels in the feature and it delivers them. No messing about.
Then comes the stronger state, Huli Spins. Five scatters unlock this mode, and here the Book of Huli stops playing nice. The official page says the book’s power is fully unleashed and all regular symbols expand, revealing deeper secrets. That one sentence changes the whole posture of the slot. Suddenly the game is not just handing out a prettier version of the same feature. It is offering a clear hierarchy. Standard free spins are the door. Huli Spins are what happens after stepping through it.
The Bonus Buy feature fits naturally into that structure. The page describes it as a swift passage to both Free Spins and Huli Spins, which makes sense because this is a slot built on two separate levels of potential. In practical terms, Book of Huli feels like the most bonus-conscious entry in the line. It is not as old-school stern as Book of Truth and not as neat and disciplined as Book of Odin. It is the one that most openly says there is another layer waiting behind the first curtain. That makes it easy to argue for as one of the strongest TrueLab book slots to date.
Book of Odin keeps the structure cleaner and lets the mechanics do the talking
Book of Odin arrived on 17 June 2025 and represents the most recent official step in the line. The page lists it as a modern slot with 1 to 10 paylines, RTP of 96.0 per cent and a top win of x10000. Its volatility meter sits around the middle with a slight half-step upward, which places it in a moderate band rather than at the wild end of TrueLab’s range. That suits the game. It is not trying to be a screaming outlier. It is trying to be a polished book slot with a solid backbone.
The theme moves into Norse territory, with Odin the Allfather guiding the way towards treasure. That kind of setting can often become bloated if a developer keeps piling on runes, ravens and pseudo-epic fluff, but TrueLab does not overdo it here. The key image is the book itself, not the wider mythology. Odin is less a noisy mascot than a guardian presence behind the feature, and that gives the slot a steadier tone.
The mechanical structure is clean and sensible. Variable paylines let the game move between one and ten lines, which changes bet size, hit rate, volatility and payouts. The special symbol here is a Wild Scatter. That is an important wrinkle because it does two jobs at once. It substitutes for any symbol on the reels except the chosen expanding symbol, and it also activates ten free spins when three or more land. That dual role keeps the book-slot logic intact while giving the trigger symbol a bit more weight in the base game.
The free spins round is classic in the best sense. Three wild scatters anywhere on the reels award ten free spins with an expanding symbol and a retrigger possibility. Before the feature begins, a regular symbol is selected to expand when it lands during the bonus. This is the sort of structure that works because it respects the simple old mechanics instead of trying to bury them under gimmicks. It lets anticipation build around symbol selection and then leaves the outcome to reel behaviour, which is exactly how a book slot should breathe.
Book of Odin also includes a Buy Bonus option, which makes it the most overtly modernised of the three games in a user-facing sense. Yet it never feels overengineered. There is no second super-stage like in Book of Huli and no True Free Spins escalation like in Book of Truth. That restraint is part of its appeal. It is the tidiest and most disciplined title in the series, and sometimes that is precisely what a Book slot needs.