ABSTRACT: The series of Joseph Fourier were an important mathematical and physical invention, and a vital spur to the development of analysis as we know it today. A deep property of Fourier series is the Theorem of Carleson asserting the pointwise convergence of square integrable Fourier series. The question, evident already at the beginning of the subject, had to wait a couple of centuries to find a resolution. This result has recently the subject of a renewed interest. I'll survey the Theorem, the sources of its enduring interest, current results, and a challenge or two for the future.