Saints Row: Gat out of Hell

Tomes are basically audio collectibles scattered around the map that look like a floating book that is on fire, and are colour coded depending on who they are for. Each of your allies has 5 books in their respective region of the map, then there are 39 Damned Souls Orientation Guide (D.S.O.G.) books scattered across the entire map. If you see any of them while working on the story you can pick them up, but you shouldn't really worry about them until you have the Collectible Finder and start working on all of the collectibles.

Both the tomes and Gat and Kinzie’s commentaries show on the map as a brown book with light coming from it, so you will have to look for all of those when you are finding all the collectibles. There isn't a separate counter for any of the collectibles, they are just called “Collectibles” on the world map and a x/x number is given for each region. Because of this it is recommended you work on these at the same time as you are finding all the soul clusters, so that you can pick up everything as you go through each area.

Note about Tomes (and Glyphs) in Co op: While playing in co op if one player collects a Tomes or Glyph that neither player have, it will count as collected for both players, regardless of how far away they are from each other when the Tome or Glyph is collected. (Thank you kfree7 for finding this out.)