Part One ESTIMATION OF RECOMBINATION 1. General survey of methods for estimating recombinational variability 2. Marker analysis 3. Marker analysis of quantitaive traits Part Two POPULATION GENETIC MODELS OF INTERACTION BETWEEN SELECTION AND RECOMBINATION 4. The Genetic system and recombination 5. Effect of recombination on population genetic structure 6. Evolution of the system controlling recombination 7. Selection for increased recombination due to environmental fluctuations 8. Species interaction as a factor in the evolution of recombination 9. Evolutionary interpretation of recombination phenomenology