Steward begins with basic concepts such as spatial and temporal coherence, diffraction and aperture, and so forth. He then works through Fraunhofer diffraction for single and double slits, circular apertures, n-slit gratings, and crystals. Chapter three introduces Fourier series and periodic structures and chapter four Fourier transforms, convolution, and correlation — all explained by application to optical systems.
Chapter five applies all of this to optical imaging, both incoherent and coherent, and touches on holography and optical processing. Chapter six looks at applications to medical imaging: the focus is on X-ray computed tomography, but short contributions by other authors cover MRI and ultrasonic computed tomography. And chapter seven looks at the study of radiation sources and astronomical applications: Michelson's stellar and spectral interferometers, partial coherence, Fourier transform spectroscopy, aperture synthesis, and the intensity interferometer.
There's not enough room in two hundred pages to go into the details of any of these topics, but enough is presented to give a broad idea of what is involved. Fourier transforms, phasor diagrams, basic optics and so forth are explained as required, or treated in appendices, but in a manner more suited as a refresher for someone who has done courses covering those topics than for a complete beginner. Fourier Optics has an obvious niche as a higher undergraduate text or an easy graduate text — or, in my case, as an accessible survey for someone with a maths and physics background who's recently taken up photography and wants to understand modulation transfer functions and other aspects of optics.