Angular unconformity: a discordant surface of contact between the deposits of two episodes of sedimentation in which the older, underlying strata have undergone folding, uplift, and erosion before the deposition of the younger sediments, so that the younger strata truncate the older.– Michael Allaby, ed., A Dictionary of Earth Sciences, 3rd ed. (Oxford: Oxford University Press, 2008) Angular Unconformity shows us a life’s work in cross-section, a restless and humane intelligence, ever searching, ever shifting, finding meaning in our blink-of-an-eye existence against a backdrop of geological time unimaginable in its scale. In this volume, the first comprehensive collection of Don McKay’s poetry, this pre-eminent Canadian poet displays his gift for thinking through metaphor, channelling a profound philosophical discourse through plain language and striking imagery. In his poetry, disciplined attention and contemplation break through the commonplace and illuminate an ecological understanding of the world as it is.