In this sequel to a novel they wrote 33 years ago, perennial collaborators Niven and Pournelle check up on popular science fiction author Allen Carpentier, born Carpenter, who 33 years ago fell out a convention hotel window and found himself struggling to flee a hell modeled on (but substantially updated from) the one immortalized by Dante.

The earlier novel, Inferno, ended with Carpentier deciding to stay in hell and try to rescue others after his traveling companion, Benito Mussolini, makes his escape. This one sends Carpenter (who has dropped the extra vowel) straight back to his starting point in hell's vestibule and covers much of the same geography, both physical and dramatic, that he encountered last time, up to and including followup visits with many of the folks he lost on his last journey.

It's fascinating to see Carpenter's reactions when others describe world events that occurred after his death, among them 9/11, and you can't fault the eclectic supporting cast, which includes, among others, astronomer Carl Sagan, science fiction Grand Master Lester del Rey, Enron chief Kenneth Lay and Virginia Tech shooter Cho Seung-Hui. It's not a bad book by any means. It passes the time. But something's still missing. Inferno was, among other things, a grand adventure, filled with cliffhangers and (deathtraps being a less-than-accurate phrase in this universe where just about everybody is already dead) damnation traps that Carpentier and company had to hustle to escape. It was also a much more deeply imagined book that did a far better job at invoking the sights, smells and—mostly unpleasant—sensations of hell. In that volume, when Carpentier and company endured horrific passages, their suffering was palpable.

By contrast, Carpenter and the other protagonists of Escape From Hell (Tor, $24.95) spend much of their time talking, the awfulness they encounter is invoked but rarely captured in the prose, and the dramatic impact feels terribly muted. Nowhere is this more obvious than Carpenter's first-person aside that he's fallen in love with his current traveling companion, Sylvia Plath. It's a potentially great twist, but almost nothing is done with it, aside from Carpenter telling us how he feels—and he has to come out and tell us about it a couple of times, since there's honestly no romantic chemistry that might have clued us in any other way.