This special issue of 'Human Heredity' discusses the use and misuse of the polygenic additive model in human genetics. This model is the cornerstone of many methods used in the study of multifactorial diseases although its theoretical foundations are not always well known to geneticists. Contributions provide an historical perspective on the introduction of the model and review the underlying hypotheses and practical applications. Bringing together the experiences and thoughts of recognized world experts, this is a must-read for every geneticist who wants to understand how measures such as heritability are computed and under which hypotheses.weiterlesen