Radio and infrared observations of circumstellar envelopes

This review summarizes the observational achievements at radio and infrared wavelengths since 1984 concerning the circumstellar envelopes of evolved stars. The main emphasis is on our increased knowledge of late stellar evolution, in particular during the asymptotic giant branch phase and the transition to the planetary nebula stage, and on the properties of gas/dust envelopes formed by stellar mass loss. It is not a critical review, and it is essentially free from historical references.