Braiding together personal, collective, and historical explorations of what it means to "go west," Amy Kaler's Half-Light: Westbound on a Hot Planet offers deep reflections on the meaning of life, middle age, and climate catastrophe. Her memoir weaves together three strands: living with the knowledge of one's own aging and mortality; the slow-moving catastrophes of climate change; and the human history of the North American settler west, especially locations that hold traces of vanished pasts. Many of the "ruins" Kaler explores--faded hamlets, bunkers, fields of cars, bends in the river--are interesting in themselves, and some serve as emblems of hope, generational commitment abandoned by contemporary heirs, faith, hubris, even carelessness. These stops are intertwined with reflections on aging, temporality, and change, making the book feel like a deeply satisfying road trip with a thoughtful friend. Moving from meditative to sobering in compelling and measured ways, Half-Light shimmers with urgency and suggestion.