B. Barbuy & Alvio Renzini 
Stellar Populations of Galaxies [PDF ebook] 
Proceedings of the 149th Symposium of the International Astronomical Union, Held in Angra Dos Reis, Brazil, August 5-9, 1991

One approach to learning about stellar populations is to study them at three different levels of resolution. First in our own Galaxy; secondly from nearby galaxies where stars can still be resolved; and thirdly in remote galaxies in which the stellar population can only be studied in integrated light. This IAU Symposium covered the entire range of galaxies in its study of their stellar populations. Interspersed with theoretical papers, the wealth of observational results provides an important state-of-the-art presentation of the progress that has been made in this field.