September 30 marks the mid-autumn festival, an appropriate time to look at Boston’s Chinatown, long one of the city’s most vibrant neighborhoods. Since the first Chinese immigrants began arriving in the 1880’s, the familiar surroundings of the neighborhood served as a transition to American life for new arrivals. Asian immigration patterns evolved with regional politics, and the area saw influxes of people from Vietnam, Cambodia, and other nations as well as other regions of China. Today Chinatown is a thriving, but crowded place, with roughly twice the population density - and about half the per-capita annual income - as Boston overall. -Lane Turner and Lisa Tuite