[dworth]

There's absolutely tonnes of books about both wars available. Reading them all would take longer than actually fighting both conflicts, I suspect.

I was going to recommend Winston Churchill's The Second World War, but there doesn't seem to be a Kindle version as far as I can see. In any case, it's a fascinating account from a key figure, as long as you take it with a pinch of salt.

Anthony Beevor has done several books based around key battles, Stalingrad, Downfall (about the fall of Berlin) and D Day. He has a knack for marrying grand strategy and the big sweeps of campaigns with small details and intimate accounts from people involved at all levels. All three are available on Kindle.

Slightly off-topic, but the BBC did two excellent and exhaustive TV series about both wars, The First World War and The World at War. They were made quite a while ago, long enough ago for plenty of the people involved to be interviewed, including senior politicians and military figures and make for fascinating viewing. Both are available on DVD, I believe. There was also a further series, The Cold War.