Introduction

The role of nuclear reactions and decays in the generation of energy in stars, including our sun, was recognized as early as the 1920’s (e.g., [1]) and was developed quantitatively in the work of Gamow[2] on barrier tunneling, followed by the independent work of Weizsächer[3, 4] and Bethe and Critchfield[5] and Bethe[6] working out the energetics and the rates of the p-p chain and the CN cycle.