You quoted it.
There hasn't been a lot revealed yet. Only a couple of collections as examples. They will not be like the magazines we have now with only a temporary effect. When you read one of the perk books it will permanently give you the benefit whether that be a % increase in some ability or a recipe unlocked (like the C4 recipe Madmole teased). The benefits of the books will work in conjunction with other benefits which is what I meant by they stack. They stack with other benefit sources. However, they do not stack with themselves which means that reading duplicates of the same exact book will do nothing for you.
This is all the info that has been revealed so far that I am aware of.
