Contents 1. Introduction . 2. Observations bearing on stellar evolution . 2.1. Types of observational information . 2.2. General character of observations , 2.3. Star clusters . 2.4. Questions posed for theory , 3. Introduction to stellar structure and evolution , 3.1. The equations of stellar structure . 3.2. The physics of stellar interiors . 3.3. Schematic life history of a star . 3.4. Main-sequence stellar structure . 4.1. Star formation 4.2. Pre-main-sequence contraction . 4.3. Detailed calculations of immediate pre-main-sequence evolu-4.4. Comparison with observation.4.5. Early solar evolution and the origin of the solar system . 5 . Post-main-sequence evolution . 5.1. Historical introduction . 5.2. Factors influencing post-main-sequence evolution 5.3. Evolution of relatively massive stars . 5.4. Evolution of low-mass stars , 5 . 5 . T h e ages of star clusters and the Sun .6. Advanced evolutionary stages .6.1. Supernovae .6.2. Horizontal branch stars . 6.3. Planetary nebulae and white dwarfs 7. The intrinsic variable stars .