I'm on a bit of a nature-writing thing at the mo, so my first list would be:
H Is For Hawk, Helen Macdonald
Finding the Mother Tree, Suzanne Simard
The Seaweed Collector's Handbook, Miek Zwamborn
Corvus: A Life with Birds, Esther Woolfson
Adrift: A Secret Life of London's Waterways, Helen Babbs. Not exactly nature, but the author and partner live on a canal boat. There is some nice nature writing but also interesting stuff about London's waterways, currently and in history.
Also, totally different, Just My Type by Simon Garfield, about fonts: who designed some of the most well-known ones and why, what they have come to stand for, how they work. Very witty and easy to read, as well as fascinating.
Memoirs: The Moon's a Balloon by David Niven is a scream; he was quite the character and what an era he lived through.
Haven't read it yet myself but am keen to read Brian Cox's autobiog Putting The Rabbit in the Hat.
And Testament of Youth, Vera Brittain. An astonishing, sad, funny, deeply personal account of how she went from a sheltered bourgeois life to being a young VAD nurse in WW2.