'Three Men In a Boat' is an odd book- part fact, part fiction, and you're not always sure where one leaves off and the other begins. The reason for this is that Jerome started out to write a serious travelogue, and humour sort of sneaked in and took over. The result of this is a mostly comedic account of their trip, interrupted occasionally by descriptive and somewhat serious passages about various places and things the friends see en route. One rather dark incident near the end of the book is particularly jarring in contrast with the lighthearted tone of the rest of the narrative.
Jerome's book starts out with the three friends deciding to take the boating vacation for the sake of their health, which they are convinced is rapidly deteriorating. It follows their ramshackle preparations and then details the trip itself with all its adventures, or more frequently, its misadventures. There is no plot to speak of: the book is a bit like their trip on the river- it meanders from one place and event to another, occasionally drifting off course or stopping off to spend a bit of time sightseeing when the mood strikes.
Though it's a bit uneven, I really enjoyed reading 'Three Men In A Boat'. Jerome derives a lot of his humour by taking situations and events which often occur in life, and exaggerating them to a ridiculous degree. He makes you laugh at them, while still recognizing the kernel of truth in his comedic hyperbole. I also liked reading Jerome's descriptions of the historical places they visited. Some of them, like Hampton Court Palace and its maze, I've been to myself and thoroughly enjoyed revisiting them in memory. His accounts of other places -like Runnymede- made me wish I'd had the time to squeeze a visit to them into my itinerary. He also, comic misadventures notwithstanding, makes drifting leisurely down the Thames seem like a lovely way to spend a week or so. Certainly travelling the river with J., Montmorency, and co. is a lovely way to while away a few hours, reading.