Provided are background materials relating the study of extraterrestrial life to common biological principles. A history of the creation of the sun and earth is included, as well as a summary of one current theory regarding the origin of life on earth. Relationships are identified regarding possible origins of life on other planets. Factors emphasized as major parameters of favorability for life are stellar mass, planetary mass, presence of liquid solvent, and acceptable amounts of radiation reaching the surface. Universal biological schemes and concepts are reviewed which may be applied in predicting what extraterrestrial life would be like under differing conditions. (CS)