 So it should not be surprising that philosophers have gravitated to genetics in an attempt to understand how that science works, what it says about the world, and what impact it has on people living in a society where there is so much focus on genes. This encyclopedia represents well this significant philosophical interest. Over 100 entries discuss some aspect of genetics, and those entries engage a wide range of philosophical questions—questions about scientific explanation, questions about the process of evolution, questions about disability, questions about race. With such diverse philosophical interest in genetics, no single encyclopedia entry could do justice to the full scope of that science and the rich philosophical attention it has received. Instead, this entry serves as a door into that philosophical world. After a historically-guided introduction to the science of genetics and its transformative impact, the piece reviews a sample of the philosophical questions that genetics has generated, with direction to entries where those topics are discussed in greater detail. The hope is that the entry will serve as an orientation to the diversity of philosophical thought concerning genetics that is distributed throughout the encyclopedia. (The entry on  evolution  provides a similar guide to the trove of entries that review philosophical discussions around that topic.) 