The story of dim sum is the story of an itinerant people. It began hundreds of years ago as a snack in the roadside teahouses of China and along the Silk Road, flourished as a leisurely brunch in the trading ports of the south and then dispersed to almost every corner of the world in the burst of 19th- and 20th-century emigration.

This migratory pattern makes the avian metaphor of Carolyn Phillips’s “The Dim Sum Field Guide” particularly appropriate. She developed her love for these “small packet[s] of unique flavors” during...