Well I'll start off by saying this is one of the funniest books I've ever read. I laughed out loud nearly every chapter. This book feels like it was written by Monty Python. The humor within is probably best pegged as wit and absurdism. So many of the jokes were just impressive to me especially some of the ones that rely on how you naturally read things and subvert your expectations like: "The ships hung in the sky in much the same way that bricks don't." The humor is really dense and pretty consistently good which is important since the humor pretty much carries the book without much help from the plot. Sometimes it feels like Adams decided that a certain page needed a joke and he just fills it with what I call randomness. The random humor is really the only type of joke that failed to land with me the majority of the time, maybe it's because I grew up in an age inundated with random humor from Nickelodeon shows like All That and iCarly to internet humor as a whole. Every time something turned into a whale (that one was really in the book) or an engine was powered by grape jelly (that one wasn't) I just rolled my eyes knowing that it was an attempt at a joke. I understand that absurdist humor needs a bit of randomness but it can be done well or it can be done fruitlessly, it's done both ways in this book, though I will say the whale bit did bear some fruit which is why I specifically remembered that example and had to make up the other.
Apart from the humor this book has only a bit more to offer. The Universe the story exists in is a perfectly crafted setting for an absurdist romp. At times it does feel like Adams starts to wish this were a vanilla sci-fi book and things get a bit dull. If he had a go at writing a serious sci-fi novel I think he would fall flat on his face. The story overall is very bland, it seems to exist to get our characters from one setting to another. I would almost guess that he had written a series of excerpts from the guide, a few micro stories and a bunch of independent funny ideas and he decided to haphazardly stitch them together into this plot. So many of the ideas are very cool and interesting as metaphysical sci-fi concepts but when they're presented in passages that are pages in length without a joke to carry them they end up being interesting without the distinction of being engaging.
The characters (of which there are very few) are all really great. They each have their own personalities, they all have things to contribute in the way of humor, and they all serve a clear purpose in the story with the exception of Trillian, on all counts. Trillian seems to plug a few holes up but isn't entirely necessary. She exists as a straight-man to Zaphod, a grounding expositor for our fish out of water Arthur, and a way to get the mice into the story.
While I think this book had some brief boring passages it would quickly get back on track every time. It isn't often that, while I'm reading a book I think to myself "I'm sure I'll be reading this again some day" I'm excited by the prospect that someday I'll read this after having forgotten most of the jokes and I'll get to experience them again. I'm looking forward to the sequels as well.
