I tagged this as "liked books" at the time. But that's not really honest, as I didn't think much of this book at all. I'm astounded that anyone has likened it to Sophie's World! In form, yes, I can see the similarity, but I'm afraid that's where the likeness ends. Where Sophie's World was a pretty interesting and serious meditation on philosophy for people not familiar at all with philosophy, Theo's Odyssey was a gluttonous mess of a book which did not manage to familiarise me with many of the salient aspects of religions which I was unfamiliar with and led me to near-despise many of the main cast of characters.
The primary thing which I would like to comment on is the changing personalities of the characters. Much like the Scottish weather can change as many times as there are minutes in a single day, the characters frequently seemed to have complete personality transplants within a page. Theo himself was at times moody and childlike and teenagerlike and angry and philosophical and wise and foolish. His completely weird behaviour around the Japanese girl (whose name I have forgotten) despite being absolutely mad about this girl from back home is just ludicrous. At first he seems serious about this new girl, and then it's as if it never happens and he's as much in love with his girlfriend as ever? I know that mercurial temperament is part and parcel of being a young adult, but this is seriously ridiculous. Also, there are several times where a seemingly “revelatory” moment will happen to Theo, and then he'll have forgotten about it less than five pages later. It wouldn't have been so bad had the novel been short but this drones on for nearly 600 pages! His aunt, too, suffers from this personality – at once doting on Theo, and being fed up with him, and being afraid for him, and being angry at him.... and so on and so forth ad infinitum. I know this book is written with young people in mind, but I really cannot fathom who would enjoy such absolutely barking mad characterisation. The whole subplot about Theo being ill and then stopping being ill because of his journey is also completely and utterly ridiculous and not in a good way.
The bits about religion themselves are okay but are often completely ruined by the “hilarious” or “thoughtful” character interjections. I don't really feel like Theo actually does learn very much from his experiences – he's a precocious brat at the beginning and a precocious brat at the end. The discussions of the religions jump about a bit too much and I don't feel like, for someone who is apparently completely unfamiliar with the concept of religion, the approach taken by his aunt would really help. Major facets of certain religions are completely skimmed over – I noticed this especially with Christianity, the religion with which I am most familiar, and I certainly felt it with those with which I was less familiar. I was not particularly impressed by this book. I give Theo's Odyssey four out of ten.