And according to Amazon, it's only been out for about a month. I didn't buy the book there on the spot, but have now added it to my wish list.
After doing a bit of research it seems Nigel Peake is most famous for his unique maps. Plus, he is in fact an tutor of architecture at Edinburgh School of Architecture, not necessarily an illustrator.
I really didn't manage to find my favourite examples of his illustrations that I saw in the book. In fact, I think only one of those images is actually in In the Wilds. The last image is from another book, 'Maps' which also looks great.
The 'drawings' section on his website seems to be under construction! I shall have to buy a book!