The Wind is Rising, by HM Tomlinson. It's a diary of the first year or so of the second world war. It has an unforgettable first line: "All we hear from Berlin is the music of marrow bones and cleavers," and is similarly vivid throughout.

It looks like you can borrow it from archive.org, but I suggest buying a physical copy. It was printed in 1941 - and I don't believe ever had a second edition - so it's on thin, wartime paper, which adds to the experience of reading it. It's like something pulled out of a time-capsule, a tangible relic of the time it covers.