I read everything Heinlein ever wrote. Mostly, I got them out of the school library but a few I bought as a teenager when they came out, like The Past Through Tomorrow which I got through the Science Fiction Book Club.
Funny that one of the books first mentioned by this article's author was Tunnel In The Sky - - it was always my favorite Heinlein book. (And it's not real easy picking a favorite Heinlein book.)