I wanted to give this a 3.5, just to be ironic. Given it a 5 compared against most other books in the genre. Being impartial and pitting it against other books in the ZF series, I'd give it a 4.5, which is good going by anyone's standards!
This book is a prequel and probably needs some context to be properly appreciated. I read this after ZF5 and was grateful to have a little bit of the old Tommy back (fans know what I mean).
My face did go a bit squinty on one page with a serious anachronism, but I'm pretty sure nobody else would even catch it. In Mark's defence, I've never read a book that didn't make my brow furrow at some point.
This is a "must have" addition to anyone who follows the series, but then I've never encountered a fanbase so galvanised and loyal to a single author!
Another triumph for Tufo and I think I speak for most fans when I say I want more Tommy!