"This is, of course, a fantasy novel, not a treatise on theology and salvation."
This is the final sentence of the Notes section at the end of this novel. This statement is both technically true and also a bit disingenuous. Its predecessor, Inferno, contained plenty of theological and philosophical ruminations and conversations, but they served the story and felt naturally integrated into the narrative. In the case of Escape from Hell, it feels more like the story is there to serve the theology and philosophy. At times it reads much like a philosophical dialogue in the classic tradition.
I did enjoy this book. I enjoy spending time in this universe, which may sound perverse since the universe in question is literally Hell. But Niven and Pournelle did a great job of bringing Dante's Inferno to life in their first book of that name, and it was fun to go back and visit familiar places while also discovering some new things (and souls) in this sequel. However, this book is too flawed for me to give it a full 3 stars. I'd rate it 2.5 (and I round down on Goodreads).
The book starts some time after the end of the previous one. Our old friend Allen Carpenter, the late science fiction author, has tried to rescue other souls, as Benito Mussolini rescued him (until they switched places at the end of the previous novel), but has so far been unsuccessful. He is frustrated and depressed and still not sure whether souls can be saved nor what is the purpose of Hell, to say nothing of his own purpose.
The first half of the book is essentially a frame story in which our Carpenter is telling his story to Sylvia Plath, who has become a tree in the Wood of Suicides. After he figures out how to free her from her tree form, they begin their journey down to the center of Hell, where the exit is located. As he spends time with her, he remarks that he thinks he is falling in love with her, albeit not in a sexual way. This is an interesting and new development in this duology (or trilogy if you include Dante's Divine Comedy). However, the authors don't really follow this development to a conclusion of any kind. And periodcially, Carpenter inexplicably snaps at Sylvia with mean and petty comments, before immediately apologizing. We don't see enough of Carpenter's thoughts and feelings to understand why he behaves this way, so it seems to come out of the blue.
Once Allen and Sylvia get on the move, the start to accrue a veritable crowd of human souls they're trying to rescue, plus joining up with another soul who, like Allen, rescues others from Hell. For my taste, the pages become overly congested with characters. It's difficult to keep track of all of them, and individuals lose their impact in the crowd. The prose itself becomes clipped and descriptions bare-boned (so to speak). The reminders of what it feels like to be there, the pain that the souls endure, become too far and few between. So we have characters who are all literally on fire carrying on an argument, with little sense of how being on fire might actually feel or how it would impede one's ability to carry on any kind of conversation. The first novel did a much better job of pacing, world building, and conveying Allen's subjective experience of what it feels like (and smells like) to be moving through Hell.
Finally, the end of this novel was just unsatisfying to me. I felt that the authors set up expectations about the range of possible outcomes and then did something entirely different. Yes, there were some portents throughout about the possibility of an... explosive ending, but not on the scale that occurred. And, again, they failed to follow through on the promises of the Allen-Sylvia relationship arc.
A few other notes. In this book, 9/11 and the Iraq War and Hurricane Katrina -- and the various types of corruption that (allegedly) followed them -- all figure prominently. Likewise, global warming, laptop computers, suicide bombers, and other things that were not really on the radar back when the authors wrote the first novel back in the early 70s. As a New Orleanian myself and also an academic who studied the recovery of New Orleans from Katrina, I was amused by the creative license that the authors took to describe New Orleans politics. In this novel, deceased New Orleans power players essentially take over a good bit of the management of Hell. Basically it's determined that the demons aren't creative or nimble enough to manage Hell successfully, so they outsource the management to human souls. Those managers then recruit more human souls, and so co-opting the damned becomes one of the ways that Hell responds and adapts to the threat posed by the likes of Benito and Allen and (in this book) Aimee, who are roaming the Inferno and helping the damned to escape.
All in all, a mixed bag, and only worth the effort if you really loved the first book as I did.