The best English language book I know of is Vesa Nenye, Peter Munter, Toni Wirtanen, Chris Birks, Finland at War: The Winter War 1939–40, Bloomsbury, 2015 (reprinted Osprey, 2018). https://books.google.com/books?id=vZ-HCwAAQBAJ (and the sequel, by the same authors, Finland at War: The Continuation and Lapland Wars 1941–45, Bloomsbury, 2016, https://books.google.com/books?id=zb6gCwAAQBAJ is also very good).

Bair Irincheev, War of the White Death: Finland against the Soviet Union, 1939-40, Stackpole, 2012, is also good. https://books.google.com/books?id=GscLDgAAQBAJ

For a book drawing heavily on Russian sources: Carl Van Dyke, The Soviet Invasion of Finland, 1939-40, Routledge, 2013. https://books.google.com/books?id=86kE0YtMhWUC

All three of these books have the advantage of being able to draw on Russian archives, formerly not available (earlier books depend almost completely on Finnish and other non-Russian sources). Irincheev is the first English-language history of the war I know of to make extensive use of the Russian archives (and other Russian sources), and presents a both-sides picture of the war. However, Irincheev is limited in scope to the fighting on the ground, largely ignoring the air war, the sea war, and politics - very fighting focussed, and land-focussed. Thus, it isn't really a history of the war as a whole, but a history of only part of it.

For a more all-round history of the war, also drawing on Russian sources: Nenye. Nenye gives all of the things that Irincheev lacks: politics (and lots of it, including background such as Finnish participation in the Estonian War of Independence in 1918-1919, Russian Karelia, etc. (much of which is more important for understanding parts of the Continuation War than the Winter War)), and the naval and air wars. Nenye's 2 books form a whole. If you're also interested in reading about both, it's an excellent coverage of the whole of Finland's participation in WW2 (Winter War, Continuation War, Lapland War) in 2 volumes. It's also profusely illustrated (most double-page spreads have at least one photo, and there are plenty of maps and other illustrations), and has many commanders' bios in text boxes. As result of that, it's a large format weighty book, rather than a convenient compact book for reading anywhere.

Van Dyke is very Soviet-focussed. This makes it an excellent second book to read on the war, for a view from the other side, to compare with the other books which are more from the Finnish side (especially the older books, where the Soviet enemy appears as an amorphous mysterious creature, making bizarre decisions and is largely cannon-fodder for the Finnish forces). This gives the view from inside the Red Army, complete with war poetry, Russian cartoons, etc.

I don't know of any good English-language memoirs.

There is one famous Winter War novel, available in English: Antti Tuuri, The Winter War, Aspasia Books, 2003 (Finnish title is Talvisota). This is the novel that the 1989 Pekka Parikka movie, The Winter War/Talvisota, is based on. Both the novel and the movie are excellent. While not history, they are accurate enough historically, and they are good literature/film. The movie is available in multiple versions: there is an approx 2 hr "international" version, and an over 3 hours Finnish version (which is the better one to get). The Finnish 4-and-a-half hour 2 part TV miniseries version has recently been released on DVD, but AFAIK without subtitles. (The other well-known Finnish war novel, Väinö Linna, Tuntematon Sotilas/Unknown Soldiers, for which I recommend the recent translation https://books.google.com/books?id=530zjgEACAAJ is about the Continuation War.)

• https://books.google.com/books?id=cAxtNgAACAAJ

• https://en.wikipedia.org/wiki/The_Winter_War_(film)