Explorations into the world of deep play—untethered, exalted states of immersion and transcendence—from the ever-dulcet Ackerman (A Slender Thread: The Changing Seasons of a Naturalist and Crisis Counseling, 1997, etc.). Play is everywhere, notes an obviously elated Ackerman. It is an aspect of culture and courtship, language and ideas; it hones problem solving and strategic thinking; it is part of staying fit: “The more an animal needs to learn in order to stay alive, the more it needs to play.” It is part of that act called learning, and “fundamental to evolution. Without play, humans and many other animals would perish.” What has Ackerman’s attention here is play that has slipped to a different level, a combination of clarity, wild enthusiasm, saturation in the moment, and wonder, where words like —rapture— and —ecstasy— feel as comfortable as an old pair of sneakers. Art, religion, risk-taking, and sports (remote, silent, floating sports like scuba, parachuting, mountain climbing) are all forms of deep play. Typical for Ackerman is a “marginally frightening state in which I would exist entirely in the tense present and feel quintessentially alive,” like piloting a small plane, although building a fieldstone wall, the sight of autumn leaves, and the sharing of friendship can also trigger an experience where time implodes or explodes or splits, and the instinctual take over. Such moments are measured more as a mood than an activity, more a “how” tha a “what.” Being an exquisite natural historian, Ackerman often deep-plays outdoors, where, knit into nature, she drinks from its miracle waters. To wit: While sharing an ice shelf with some penguins in Antarctica, “out of the brilliant blue emptiness snow began falling in a confetti-sparkle of diamond dust. I was standing in a kaleidoscope.” Words may never do it justice, and likely Ackerman’s come as close as they ever will, but there is no mistaking deep play—or flow state or runner’s high or what-have-you—where something startling takes place that won’t be forgotten.