"The code book" is a good introduction to history and basics "Elliptic Curves: Number Theory and Cryptography" is a great, and detailed, text for understanding

"The code book" is a good introduction to history and basics "Elliptic Curves: Number Theory and Cryptography" is a great, and detailed, text for understanding ECC https://www.cwu.edu/math/kryptos https://www.cwu.edu/math/kryptos <-- competition https://cryptopals.com/ https://cryptopals.com/ <-- Awesome resource for getting started with crypt-analysis solutions