>>12804064depends on what you mean by that.
I'm not literally at my desk 24 hours a day grinding through the book. The way I do it is I work on the material from 8am to 5pm (the same as my work hours) taking breaks whenever I feel fatigued (I'm on one such break right now.)
As for staying focused, I don't really know what to tell you I just really like the material. Even in the first couple chapters when it was really boring the exercises were enough to keep me engaged since it was my first exposure to writing proofs.
