[vpjosh]

I read this when I was a teen and liked it. It explains how computers work, and is still relevant 20 years later.

https://en.wikipedia.org/wiki/Code:_The_Hidden_Language_of_C...

[Jtsummers]

Code is a good motivator (and I need to buy a second copy, my copy was loaned out and then we both switched jobs, oops). A good follow-on is The Elements of Computing Systems (nand2tetris course) which starts with a more "hands-on" approach to the material in the second half of Code. "hands-on" because it's all via simulations and idealized components, but it's a good course and a motivated teen could work through it with some guidance or solo.