If you're a fan of espionage and secret agent fiction (and as I've mentioned before, I read a ton of it during the Sixties and Seventies and still read some from time to time), I highly recommend that you check out this site. Just be prepared to spend quite a bit of time there.
I chose that Nick Carter cover to go with this post because HANOI was the first Nick Carter novel I ever read . . . but not the last, by any means.