Twenty-two ideas about how behavior actually changes, arranged in the order your year will hand them to you. Week one. Then the room you study in. Then month three, which is where most people leave. Then the first ninety days of the job, which nobody warns you about at all.
The fix is not discipline. I want to say that early, because discipline is what everybody reaches for and it is the wrong tool. The fix is that you change what your week looks like, so that continuing costs you less than quitting does. That is the entire book. Everything after this is the machinery.
The skeleton of the argument, four parts and a set of small repeated actions, I owe to James Clear, whose book on habits is better than most of what has been written on the subject. The claims here are mine, the scenes are mine, and where I think the popular version of an idea has gone further than the evidence supports, I say so.