This is volume 4 of Planets, Stars and Stellar Systems, a six-volume compendium of modern astronomical research, covering subjects of key interest to the main fields of contemporary astronomy. This volume on "Stellar Structure and Evolution" edited by Martin A. Barstow presents accessible review chapters on Stellar Structure, Stellar Atmospheres, The Sun as a Star, Asteroseismology, Star Formation, Young Stellar Objects and Protostellar Disks,...