Invited_talk abstract details

The problem of pre-PN mass loss may be separated into three parts, each requiring somewhat different modeling and observations to resolve. These three parts are: (a) At what luminosity does the mass loss end the AGB evolution, and how does this vary with M and Z? (b) What are dM/dt and v_{infinity}(t) once the star reaches this luminosity, until the envelope is almost entirely gone and the star leaves the AGB? (c) What produces the rich asymmetries of the final outflows? This review will focus on the first two questions, but the third affects our understanding of the first two if most PNe are shaped by processes that can also modulate dM/dt.