Provides the basis for understanding the genetic principles behind quantitative differences in phenotypes and how they apply to animal and plant improvement and evolution.

*Genetics Constitution of a Population *Changes of Gene Frequency *Small Populations: I Changes of Gene Frequency Under Simplified Conditions *Small Populations: II Less Simplified Conditions *Small Populations: III Pedigreed Populations and Close Inbreeding *Continuous Variation *Values and Means *Variance *Resemblance Between Relatives *Heritability *Selection: I The Results of Experiments *Selection: III Information from Relatives *Inbreeding and Crossbreeding: I Changes of Mean Value *Inbreeding and Crossbreeding: II Changes of Variance *Inbreeding and Crossbreeding: III Applications *Scale *Threshold Characters *Correlated Characters *Metric Characters under Natural Selection *Quantitative Trait Loci