I have bought many "Dummies" and "Idiot's Guide" books for my son (don't like the titles, but he reads them). Isaac Asimov wrote lots of science books for the layman, listed at http://www.asimovonline.com/oldsite/asimov_catalogue.html , of which my children have read several. His NYT obit http://www.nytimes.com/books/97/03/23/lifetimes/asi-v-obit.html is an interesting profile of a gifted and productive man.

"His usual routine was to awake at 6 A.M., sit down at the typewriter by 7:30 and work until 10 P.M."

That's how he wrote 500 books.