This book is a collection of the author¿s publications in the area dealing with the light beams with flat-topped profiles. In Optics Communications 2002 January issue and in Optics Letters 2002 June issue the author proposed the necessary condition for generating optical beams with nearly uniform profile. This proposal leads to the introduction of a set of light beams with flat-topped profiles that can be expressed in terms of a finite series of the lowest-order Gaussian modes (TEM00) with different parameters. The computational advantages of TEM00 provide convenience in a number of successive publications regarding the generation and propagation features of flat-topped beams and their applications to the generation of Bessel-Gaussian beams and an analysis of the influence on the readout signal on the height profile of the pits (or bumps) on optical discs.