Inventing the Internet (https://mitpress.mit.edu/books/inventing-internet) is a fantastic place to start

Innovations in Internetworking (https://www.amazon.com/Innovations-Internetworking-Artech-Te...) is a great collection of papers that help you understand the original thinking behind each protocol

The Elements of Networking Style (https://www.amazon.com/Elements-Networking-Style-Animadversi...) explains why you see only 4 layers in the real Internet while ISO slices it into 7 and all the fun parts os standard bodies while retaining a unique sense of satire