Summarization is actually a less effective learning technique, according to Dunlosky and other literature in cognitive learning science. Dunlosky recommend othe

Summarization is actually a less effective learning technique, according to Dunlosky and other literature in cognitive learning science. Dunlosky recommend other techniques namely "practice testing" and "distributed practice". So I guess those more powerful (and time consuming) techniques are worth using if the book is worth learning thoroughly, whereas summarization and outlining, etc. are less mentally challenging/effortful techniques but still somewhat useful, just empirically less proven to be very effective.