That must be some special magic skill to make a book out of a "chunk of C4" and getting it to explode like a "chunk of C4", especially in the absence of detectable metal and charge.

There is plenty of technology around that can differentiate between a book and a chunk of the material you mention but the TSA is rather more interested in wasting money on obsolete junk technology includine that the TSA is using to to observe passengers naked. Then there is all the other wasted money that is a product of TSA's wasteful processes that are part of its expensive dog and pony show.