What is the theme in Moon Tiger by Penelope Lively?

Historical Contingency is the main theme. Claudia’s world is a godless world and for that reason, it is a place of chance rather than destiny. Claudia is deeply affected by the utter arbitrariness of historical fact. In one striking example of this, she describes how the price of fur in England dictates the value of wampum in America. The role of chance in history is something Claudia acknowledges and celebrates while also militating against it. The trauma of losing Tom is senseless because arbitrary, but at the same time her ever having met Tom at all is also a historical accident, so in the end, it becomes impossible to say whether the terms ‘contingency’ and ‘necessity’ mean anything to a complex historical mind. Claudia cannot make sense of the events in Tom’s diary even though these events are so real they are almost palpable to her.