Computation Theory and Why Hard Problems Matter
Sections 1.3 and 1.4 of Computational Number Theory and Modern Cryptography are the moment the textbook stops warming up. Song Y. Yan, ISBN 978-1-118-18858-3, finally names the problems the rest of the book will live inside. I read this as the whole map on one table. Computational number theory, the hard problems, then modern crypto after the 1970s.