The Fractional Fourier Transform provide a comprehensive and widely accessible account of the subject covering both theory and applications. As a generalisation of the Fourier transform, the fractional Fourier transform is richer in theory and more flexible in applications but not more costly in implementation. This text consolidates knowledge on the transform and illustrates its application in diverse contexts. Applications studied so far fall mostly in the areas in optics and wave propagation and signal processing, including optical information processing, beam synthesis,...