What is the theme in So Long a Letter by Mariama Ba?

Money runs through the many currents of this story - freedom, marriage, loyalty, choices, family. The movement to emancipate women consistently encounters the same stumbling block: money. With women uneducated and in their houses, they remain dependent on their husbands for all of their needs. Binetou and young Nabou will always be tied to their husbands - they won’t have the means should they ever choose to leave. Aunty Nabou ensured Nabou’s limited education, and Binetou’s mother drove her to marriage for the sake of money.