|Wolfgang Baur Contributor; Publisher, Kobold Press; RPG Superstar Judge|
Love to see a couple reviews for this bad boy!
The nice thing about The Book of Lairs is that there are no stat blocks within - the various encounters only indicate the name and quantity of a given monster.
So, even folks that only play Pathfinder could still use this book - simply use the Pathfinder stats for any monster listed that has Pathfinder stats, and then either wing it (if you also have the Tome of Beasts book) or replace that monster with something similar.
Bottom line - there are a lots of very cool encounters/lairs (each with awesome map of said lair!) in this book and Pathfinder fans can still get almost as much fun from this book as 5E fans! :)