This is the second 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. The first talk covered the geometry point of view of kneading maps, but this time we will focus on the combinatorial definition of kneading maps. This is also the very first definition due to Hofbauer. If time permits, we will show that these two views coincide.