Farnham's Freehold

My circadian rhythms are all out of whack. I keep waking up at 5:00 a.m. and I can't get back to sleep. This morning, I sat up and finished reading Farnham's Freehold. The cover proclaims it to be "Science Fiction's Most Controversial Novel". I wouldn't go that far, but I can see how it may have been controversial when it was originally published. Admittedly, I'm a huge Heinlein fan, but this isn't my favorite of his books, it's an intriguing read, but seems to be more of a fantasy about time travel, racial role reversion, and nuclear war, than a real science fiction novel.