The first activation pass is usually the whole book textbook or whatever to become familiar with it. The next passes can be the whole book again depending upon the size of the book, how familiar you are with the topic and what you want to get out of the book. Textbooks are often activated chapter by chapter using as many activation passes per chapter as required.
Usually we take the book as a whole since going over it again with the next activation pass we pick up more information that we may have skipped in the first passes.
Alex
