The author assumes you know how to program, and teaches you how to program in Python. He does this by, at the beginning of a section, presenting a working chunk of code between 10-30 lines long. Then he spends the rest of the section explaining what those lines do, and explaining when you'd want to use those techniques. I liked this approach because I knew where he was going in each chapter, and I could use my own experience as a programmer to figure out what was going on, and skip his explanation if I already figured it out.