Neil Gaiman has a lot of respect for Douglas Adams' work and quirkiness, and therefore you can feel the endearment just from reading. The book is funny - mostly through footnotes - and I learnt a lot that I wouldn't say is essential to understand Adams, but it planted a willingness in me to read everything again. I even want to listen to the original radio series. This book is worth reading if you enjoy Douglas Adams the man, and not exactly for Hitchhiker's Guide even though it is a big chunk of him.