This week, we’re diving back into the fascinating world of numbers, from the toughest theoretical concepts, to the numbers that describe our favorite pastimes. Guest host Rachelle Saunders talks to science writer Brian Clegg, about his book A Brief History of Infinity: The Quest to Think the Unthinkable, which describes the surprisingly human endeavor to understand and describe the unimaginably large concepts that define the universe. And Desiree Schell talks to physicist Aaron Santos, about his entertaining new book Ballparking: Practical Math for Impractical Sports Questions.