This is the first talk of the summer series of differential dynamics. This series aims to study the kneading invariant and kneading maps of the members in a paper of Gamaliel Ble. As the first talk, several essential notions will be discussed, including dynamics of piecewise monotone functions, especially of unimodal functions, Kneading Invariants and its decomposition, the one-to-one correspondence between Kneading Invariant and Kneading Maps. Several examples will be illustrated.