160 pages hardcover, A5 size
As it says, this book contains all the rules you need to play Lamentations of the Flame Princess. They rules can be used in any fantasy setting - it doesn't have to be weird.The first half of the book covers the flesh and bones of the rules with character creation, rules for adventuring and encounters, and even how the player characters can invest their hard-earned treasure. The second half is all about magic. There are the obligatory spell lists, but you won't find fireballs here (see below), and their is a definite weird tinge to some of the spells. The Summon spell in particular: it is a first level spell that allows any magic user to someone strange and eldritch creatures, but get it wrong and you could flood the entire planet with milk, or disrupt the very nature of time itself. Magic using characters can create their own potions, scrolls and magic items, using the rules described here. They can even research new spells, whether these are spells from the lists or completely new spells (so you can create a fireball spell if you really want to).
The firearms rules are covered in an appendix and are well researched and detailed. These are not simply variants of crossbows, but have their own special rules for use against armour. After all, it was the introduction of mass firearms that led to metal armour effectively disappearing from the battlefield. Firearms are completely optional, like any of the rules of any RPG - if they don't fit your group's style of play, don't use 'em.
The artwork, on the other hand, is definitely part of the weird setting for the game, and is the reason why this rulebook has an 18+ rating. If you want the rule book with the gruesome artwork, you can download a free, art-free copy of the rules below.