Book version of the UK TV series (which I haven't seen). While the four individual sections (Coldest, Driest, Hottest, and Wettest) are enjoyable, I was disappointed that Nick Middleton makes no effort to connect the sections or even come to any overall conclusions about why people live in such extreme realms.
In addition, the sections themselves seemed occasionally padded. The Driest section is the worst offender, with a lengthy section on living at extreme Andean altitudes, which, while fascinating, isn't related to the main topic (this is ironic to me since it's the main reason I bought the book, having visited -- for twenty minutes -- the airport at Arica, Chile, enroute to La Paz, and being curious about this desert beachfront place).
The best section is the first, being a rather vivid look at the peculiar adaptions the people in that Siberian town make to live with (as well as some fascinating descriptions of the phenomena associated with) extreme cold.
Perhaps the TV series is more enlightening, but since it's not out on DVD yet, I can't find out.