Can reindeer fly? Why is Santa Claus fat? Was the Star of Bethlehem really a comet? Will scientists succeed in creating the perfect Christmas tree by cloning? How do snowflakes form, and what could we do to guarantee an annual White Christmas? How does Santa manage to deliver presents to an estimated 842 million households in a single night? Why is Rudolph's nose red? These are among the questions explored in an irresistibly witty book that illuminates the cherished rituals, legends, and icons of Christmas from a unique and fascinating perspective: Science.