Nearly 2,000 years ago, the Roman scholar Censorinus bestowed upon his best friend a charming birthday present: "The Birthday Book", which appears here in its long-awaited first English translation. Laying out everything Censorinus knew about birthdays, the book starts simply; but by the conclusion of this brief yet brilliant gem, Censorinus has sketched a glorious vision of a universe ruled by harmony and order, where the microcosm of the child in the womb corresponds to the macrocosm of the planets. Alternately serious and playful, Censorinus touches on music, history, astronomy, astrology, and every aspect of time as it was understood in third-century Rome. He also provides ancient answers to perennial questions: Why does the day begin at midnight? Where did Leap Year come from? Which came first, the chicken or the egg? Embodying the proverbial gift that keeps on giving, "The Birthday Book" has long been treasured by scientists, poets, and scholars, and Holt N. Parker's graceful and lively new translation - accompanied by an illuminating introduction and detailed notes - is itself a present for Latinists, historians of science, and anyone looking for an unusual birthday gift.