I know you did not ask me, but:
The Moon is a Harsh Mistress
Starship Troopers
Starship Troopers
Heinlein wrote so many, and I’ve read a bunch, and haven’t even scratched the surface. I’d start with his classic, Stranger in a Strange Land, and then The Moon is a Harsh Mistress. The Number of the Beast was intriguing. many of his later works are sequels to those two. Oh yeah, don’t forget Starship Trooper, both the book and the movie, and Time Enough for Love. Friday was also quite good. Revolt in 2100 and Methuselah’s Children. His mind was quite fertile and sometimes quite warped.