Scalar diffraction from a circular aperture is a ubiquitous problem that arises in a variety of disciplines, such as optics (lenses), acoustics (speakers), electromagnetics (dish antennas), and ultrasonics (piston transducers). The problem endures despite centuries of research because each new generation of researchers rediscovers it and adds some novel insight or new result to the existing literature. Scalar Diffraction from a Circular Aperture promises a few new results and several novel insights, particularly with regard to spatial averaging. Although the text emphasizes...