The determination of stellar ages is crucial for the development of our understanding of the universe and for constraining theoretical models of galaxy formation and planetary system evolution. The ages of stars provide scientists with timescales to identify the relevant physical processes responsible for the development of the cosmic structures.

Age-dating stars describes in a simple, yet rigorous manner, the vast array of techniques used to determine stellar ages. It also explores how these ages inform our knowledge about planets, star clusters, galaxies and even distant galaxies that we cannot resolve into individual stars. Up-to-date with the latest research and technologies in the field, it discusses open problems that remain to be pondered in future research. This second edition includes a new, comprehensive introduction to the main concepts of asteroseismology, the use of asteroseismic observations for age determination and for probing the internal structure of stars, an updated analysis of the uncertainties on the age estimates, new results about the ages of stellar populations in our galaxy and high-redshift galaxies gathered observations from the Gaia satellite and the James Webb Space Telescope, and the new/upcoming observational facilities relevant to the subject.

• Presents an entertaining and accessible approach whilst also providing a rigorous and comprehensive presentation of the subject.

• Describes how to unveil the ages of stellar populations in the universe, even in distant galaxies that we cannot resolve into individual stars.

• Contains historical notes about these techniques, outstanding major problems, and a discussion on future developments in the field.

It will be of interest to undergraduates and graduate students studying astronomy, and to readers from diverse backgrounds.