Waterlog is the quintessential book about outdoor swimming. Written at a time when swimming outside (especially inland) was still considered eccentric, if not outright subversive, Waterlog kick-started a revival in outdoor swimming which continues today.
Deakin's prose is inspiring and romantic - often overly so - but, by his own admission, Waterlog was never intended to be a guide, let alone a definitive one.  It is, rather, a celebration of swimming, of being outdoors and of enjoying these things for their own sake. Sadly, enjoying our outdoor spaces still feels like an act of rebellion, much like it was for Deakin nearly thirty years ago.
If you're not already inspired to make the most of the wild spaces we have left, and reading Waterlog doesn't at least get you interested then I really don't know what to say to you.