Title: The Ultimax Man
Description: In 1970, Keith Laumer was in the process of writing this book, and he had a severe and ultimately debilitating stroke before he could finish, and it shows.

The first half is great: Damocles Montgomerie is a gangster who had been shot and severely wounded, only to have his life saved by a mystery man. But this mystery man turns out to be a space alien, and he has plans for Damocles-namely to make him into a superman with extreme intelligence and skills, as well as strong physical power. Damocles complies, but the alien threatens to destroy him with his experiment done, and Damocles takes the alien's spaceship to the alien's own world, despite desperate pleading from the alien that he would be left stranded on Earth.

Unfortunately, the second half is a disjointed mess, with events and characters that seem to appear at random. It turns out Damocles had been tricked by the alien and he was meant to come here, but the story has become a mess, as if Laumer had an ending planned but couldn't for the life of him recall what he intended it to be.
Subjects: Fiction in English, Life on other planets, Fiction, American Science fiction, Fiction, science fiction, general