I'm close to finishing
Mastering Bitcoin: Programming the Open Blockchain by Andreas M. Antonopoulos
Its been really good so far. I'll definitely keep this book close by to use as a reference time to time.

I plan to read next
Bitcoin for Nonmathematicians: Exploring the Foundations of Crypto Payments by Slava Gomzin
Slava Gomzin is co founder of the GRAFT Network block chain.