In the late 18th century, surveyors divided the Midwestern United States into the Jefferson Grid: a system of neat, one-by-one-mile squares. But because the earth is round, the lines tapered to the north. Therefore the grid had to be corrected: every 20 miles, grid corrections brought theory and practice back together. Pilot and aerial photographer Gerco de Ruijter (born 1961) first spotted these small bends and T-junctions while completing a residency in Wichita; then, with the help of Google Earth, De Ruijter found thousands of these corrections. Presenting De Ruijter's selection of over 250 photocollage grid corrections--snowed under or dried up, in cities and in deserts--and featuring an exceptional design by Irma Boom, this publication is a work of art and monument in one, a testimony to the human urge to design the landscape and the ways in which nature responds to that urge.