In the early years of the 23rd century, archaeology has expanded to the stars. Teams of linguists, historians, and engineers are excavating ruins on a number of planets in search of clues about the Monument-Makers, whose civilization was leaving its mark on distant worlds when our ancestors were inventing the wheel. Coming from a planet whose population has outgrown its resources, these archaeological teams must race to finish their work before colonists from Earth are sent to occupy these worlds. Priscilla ""Hutch"" Hutchins serves as pilot for one of the teams. Though untrained in archaeology, she's the one who first sees connections between the spectacular monuments left on various worlds and the peculiar, massive false cities made of solid cubes of rock. These cities, composed only of right angles, appear with regularity throughout the galaxy; all show signs of having been subjected to massive destructive forces. Scientific curiosity and grief over the accidental death of their leader take Hutch and the remains of the team to the edge of the galaxy. There they encounter the Monument-Makers and are faced with a mystery whose solution may hold the key to human survival. McDevitt (The Hercules Text, not reviewed) is at his best award-winning style in this intelligent and wide-ranging novel.