> I definitely got the impression this was Heinlein speaking in his own voice / his own opinions.
That's exactly what I'm talking about! Read another book, and he'll be speaking his own voice/opinions, to, but they'll be very different.
On books, Heinlein's must read, in my opinion, is "The Moon is the harsh mistress", "Stranger in a strange land" and "Starship troopers", all three being very different. But the one book I would recommend reading first is his lesser known novel, "The door into summer". It is not groundbreaking, but very warm and charming.
I'd recommend The Moon is a Harsh Mistress which is a romp imho, and also happens to be a better insight into his personal politics.
Also, Have Spacesuit Will Travel, Farmer in the Sky, Stranger in a Strange Land and mostly everything by Heinlein, though there was arguably a bit of a drop in quality towards the late end of his career.
I like to think of it as 'early' Heinlein and 'late' Heinlein - although both periods are very enjoyable, sometimes it as if it's two different authors.
I ask because when I read it (way back when), I definitely got the impression this was Heinlein speaking in his own voice / his own opinions.