The achievements of great mathematical thinkers from ancient times to the modern age are examined through engaging, accessible text. Fascinating profiles of time-measurers like the Mayans and Huygens, arithmeticians like Pythagoras and al-Khwarizmi, logicians like Aristotle and Russell, and many more. Readers can follow along on these thinkers quests to explain the patterns in the world around them and to solve a wide range of theoretical and practical problems.