[runjake]

  > Many times the author tries to say the same thing 20 different times to fill a book. Many of those books could have been a great 30 minute presentation.

This is indeed how many, many of these books started -- as a $x minute presentation or an article.

I always try to find the source presentation or article and consume that before reading a book. It has served me well. You get the core ideas, concisely, without the fluff.