Play and The Heart’s Refusal to Harden, by Lisa Kosena Forbes
https://playstorypress.org/books/play-and-the-hearts-refusal-to-harden/

Play and the Heart's Refusal to Harden challenges the belief that play is something we outgrow. Drawing from psychology, play therapy, education, social critique, and personal experience, Lisa Kosena Forbes explores how cultures recruit us into seriousness, productivity, and disconnection—and how play helps us resist.

This is not a book about becoming more playful for the sake of having fun. It is a book about remaining alive in a world that often asks us to harden. Through stories, humor, research, and reflection, Forbes examines why so many adults lose access to play, how social systems shape our relationship with aliveness, and why play can be a powerful act of curiosity, connection, imagination, and hope. For anyone who feels exhausted, disconnected, overwhelmed, or stuck in survival mode, this book offers a different question: not "How can I play more?" but "What conditions help people come alive?"