Here printed as a separate volume, with beautiful illustrations from an 18th-century treatise on the Mexican calendar, the late Nobel laureate's premier long poem. Piedra de sol was the 1957 poem "that definitively established Paz as a major international figure" (Sagetrieb). Written as a single cyclical sentence, Sunstone is a tour de force of momentum that takes as its structural basis the circular Aztec calendar, which measured the synodic period of the planet Venus (584 days -- the number of lines in the poem).