My smallest book is 4"X7"x1", "Bushcraft" by Richard Graves. I had it many many years and it's on it's last leg. Next would be "Camping and Woodcraft" by Horace Kephart 4"X7"X2", this book is jammed packet with survival info. Not exactly pocket size but pack-able. If your looking for something to carry on you that will fit into your pocket, you might try Izula Gear Card Sets. Smokey Mountain Knife Works sells them in their catalog. These are 30mil plastic credit card stock information cards. I seen two different sets, one had survival info printed double side of 4 cards , the other was for navigation with 3 transparent map cards and 2 double sided cards with navigation instruction and basic survival. Each set was $9.99.