In Friendship, science journalist Lydia Denworth takes us in search of friendship’s biological, psychological, and evolutionary foundations. With insight and warmth, Denworth weaves past and present, field biology and neuroscience, to show how our bodies and minds are designed for friendship across life stages, the processes by which healthy social bonds are developed and maintained, and how friendship is changing in the age of social media. Blending compelling science, storytelling, and a grand evolutionary perspective, Denworth delineates the essential role that cooperation and companionship play in creating human (and nonhuman) societies