Niven and Pournell have taken Dante's Inferno and given it a sci-fi twist. The basics of Inferno are there, the vestibule of Hell, the concentric circles of Hell, the woods of the suicides and so on. Each area is designed for a different 'sin'. Instead of Virgil journeying through Hell we have a dead science fiction writer, who doesn't believe in an afterlife, being guided by a well known historical figure...I won't give the name away and spoil the surprise.
The writers have produced a funny, fast paced romp of a book, albeit somewhat brief, that will have you laughing aloud at times, cringing at others, but also figuring out how many areas of Hell you could end up in. There is nothing high brow about this book and it makes no pretence at being a literary work of art. It is produced purely as a quick, fun read and this is a job it does admirably. It is an old book, long out of print but scheduled for a re-print. If you can grab a copy, you won't be disappointed.