The title of this remarkable archaeological travelogue is derived from the presence of deep layers of dust in the Wonderwerk cave near Kimberley, where the dust represents successive layers of human occupation dating from at least a million years ago. The author observes, “in the cave our life is just one millimetre of dust. The years of iron and steel and all of recorded history measure just a little more.” (p.182) These words reveal the huge time-span of human history in South Africa, as observed by the author and her family during a car-trip to various archaeological sites between Muizenberg in Cape Town and Kuruman in the Northern Cape. Martin (a lecturer in English at the University of the Western Cape) writes with deep and pensive emotion about everything on her journey, including the pleasures and tribulations of being a mother with often-fretting children on a long car-journey, and the personal detail adds another layer to the many strata of the book. Her descriptions of everything from stone artefacts to impala to wild flowers, and from moonlight over semi-desert to squatter shacks are vivid and evocative.