Herbert Morrison - Portrait of a Politician by Bernard Donoughue and G.W. Jones is a very good book examining the life of one of the major figures in the Labour Government of 1945. It is in the most part a well-written and detailed work, but does suffer from a slightly disjointed nature as the two authors wrote their respective halves separately.
Herbert Morrison was for a number of decades the man who organised the Labour Party. First, at a local, and then at a national level, he helped shape the policies and create the structures that allowed the Party to not only compete but to win elections by appealing to the nation as a whole. Unfortunately, however, the actions that he took to achieve this made him a multitude of enemies, especially on the left, and created the impression that he was the British equivalent of a US party boss (a caricature not helped by his involvement in plots to replace Clement Attlee on numerous occassions). This reputation, unfortunately, played a major role in Morrison not fulfilling his ambition of becoming leader of the Labour Party.