The interest earned on a bank account, the arrangement of seeds in a sunflower, and the shape of the Gateway Arch in St. Louis are all intimately connected with the mysterious number ^Ie^N. In this informal and engaging history, Eli Maor portrays the curious characters and the elegant mathematics that lie behind the number. Designed for a reader with only a modest background in mathematics, this biography of ^Ie^N brings out that number's central importance in mathematics and illuminates a golden era in the age of science. "This is a gently paced, elegantly composed book, and it will bring its readers much pleasure.... Maor has written an excellent book that should be in every public and school library." --Ian Stewart, New Scientist "Maor wonderfully tells the story of ^Ie^N. The chronological history allows excursions into the lives of people involved with the development of this fascinating number. Maor hangs his story on a string of people stretching from Archimedes to David Hilbert. And by presenting mathematics in terms of the humans who produced it, he places the subject where it belongs--squarely in the centre of the humanities." --Jerry P. King, Nature "Maor has succeeded in writing a short, readable mathematical story. He has interspersed a variety of anecdotes, excursions, and essays to lighten the flow.... [The book] is like the voyages of Columbus as told by the first mate." --Peter Borwein, Science