Our concepts of the sun have been altered by four new developments--the discovery of apparent global solar oscillations, an unsettled and unsettling deficit of neutrinos from the center of the sun, a new elucidation of the role of solar wind, and some disturbing historical facts that shake old concepts of solar constancy and regularity. This volume brings together summaries of these four developments in solar physics, written by the four scientists whose work has prompted our new assessment of the sun.