It is typically said that there is natural selection on the genetic variation that affects ecological performance, but this description seems too simple. In The Selective Organism, Pim Edelaar presents two cases that cannot be understood using the standard theory of adaptive evolution. Traditional interpretations of the three classical requirements for adaptive evolution—variation, selection, and inheritance—have been too narrow. The Selected Organism confirms that our biological interpretation of each requirement can be expanded.A mathematical exploration of the consequences of the expansions of variation, selection, and inheritance shows that many consequences only involve the quantitative outcomes of the evolutionary process, and several are already well known. However, we also encounter a qualitative change in how the evolutionary process can operate: there is now a second driver of adaptive evolution. The first and classical driver, involving natural selection, can be summarised as 'selective reproduction of heritable variation'. The second driver can be summarised as 'selective production of heritable variation', since here the selective process comprises the developmental decisions made by the organism. This expanded theory of adaptive evolution can satisfactorily explain the two puzzling case studies, as well as a diversity of other biological phenomena, such as epigenetic inheritance and cultural evolution. Edelaar integrates these expansions into a visually appealing causal model. These developments hold a range of important theoretical and philosophical consequences and provide many suggestions for novel and insightful empirical research.