As an avid reader, I positively DEVOUR Heinlein. Poly aside, he just spins a damn good yarn. Re-read his books often to fully grok them - he's one of those "gain a littel more from it each time you read it" authors. Herbert, Card, Stephenson - even Clancy. All my favorites are like that.
PS - "grok" is in the dictionary. I actually used it in a Scrabble tourney once and got challenged - and won, lol. Laughed my butt off the first time I found it in the abridged.