Written by psychologist Darby Saxbe, this book explores how becoming a father reshapes men's bodies, brains, hormones, and sense of purpose. Drawing on two decades of research, from hunter-gatherer communities in the Congo to everyday suburban dads, Saxbe makes the case that fatherhood isn't just something that happens to a man's life, it actively changes who he is at a biological level.

A recurring theme worth knowing before diving in: fatherhood doesn't just affect kids and partners, it changes dads too, sharpening paternal instincts, and even correlating with more resilient thinking in later life. Recommended for any dad curious about the science behind the changes he's feeling, not just the parenting tips.