This book originates from the teaching accumulation and curriculum construction achievements of eecs for many years. It is a supporting textbook for Peking University's * * * excellent resources and national excellent courses. 1 version was rated as * excellent teaching material for higher education. It is the designated teaching material of discrete mathematics course for undergraduates in Peking University, and it is also the teaching material of discrete mathematics course on Coursera platform for large-scale open network course teaching. Tsinghua University Publishing House has developed a wealth of online teaching resources for the third edition of the main textbook, which can be practiced and tested on the online teaching platform of Tsinghua University Publishing House to realize interactive teaching and intelligent learning.