"O wondrous exchange!" Of all the seasons of the church calendar, Christmas is the one most recognized and celebrated by our society at large. That means it's the season we're most familiar with—but that can also make it harder to see past Christmas' many cultural trappings to its timeless beauty. At the first Christmas, God exchanged the glories of divinity for the vulnerability of human existence, uniting himself to us in order to unite us to God. In this short volume, priest and theologian Emily Hunter McGowin invites us into the church's celebration of that great exchange, in all its theological and liturgical splendor. Each volume in the Fullness of Time series invites readers to engage with the riches of the church year, exploring the traditions, prayers, Scriptures, and rituals of the seasons of the church calendar.