I just finished a more-than-600-page long book (Tic-Tac-Toe theory) about combinatorial games, focusing on tic-tac-toe like games. In this talk I will discuss the main theorems and the main techniques in a rather informal way. I will attempt to answer basic questions like:

1. why are games so difficult?
2. what are the hopeless problems?
3. what can contemporary combinatorics do?
4. what are the surprising consequences of ``tic-tac-toe theory"?