I've been reading Atkinson's Liberation Trilogy, and he says that the US had 8 million men mobilized (thought not all of them were actively fighting). Is there a source for maximum army size of the other nations? In particular, I'd like to know the maximum number of troops the British Empire fielded. I know that India had 2.5 million at its peak, and I think the UK proper mobilized 3-3.5 million, but what about the rest of the empire?