Hugh Laurie (known to Americans as House) wrote a novel called The Gun Seller, and it is fantastic.

Interesting fun fact I learned on the DAVIDGERROLD forum on CompuServe in the 90’s: David Gerrold, the author, knew Heinlein, and ended up taking care of Heinlein’s cat after he died. And then the cat ran away.

That means the cat that inspired Pixel in The Cat Who Walks Through Walls disappeared and it was David Gerrold who lost Heinlein’s cat.