Great Writer! Unfortunately, I think he started going looney at the end of his life. He also developed a penchant for flirting with incest in his books (Lazarus Long, 'Time Enough for Love' and other references). His books suffered at the end and were somewhat disjointed and he had a quixotic view of religion.
I started reading him in the 70's when I got drafted and eagerly awaited every new novel. My most favorite memories are "Glory Road," "Time Enough for Love," and "The Moon is a Harsh Mistress," (which I consider the best). 'Troopers' is one of his earliest works and wholly not representative of the best of which he was capable.
Take some time (perhaps more than that) and read the rest.....
I tend to agree. He was pretty much gone into the esoteric by the early seventies. But from 58 until 71 or so he was a machine - Troopers, Stranger, Moon (my favorite) Glory Road, even Farnham's though I know not everyone likes that one.
I like pretty much all his shorts though, and his early novels were fun if a bit superficial at times (Double Star, Puppet Masters, Sixth Column, Tunnel in the Sky, etc.) I've read most all of them just because I like his style.
It saddens me that a man who could write such razor crisp shorts as "All You Zombies..." and "...He Built a Crooked House" could lapse into writing something like Number of the Beast.