Various classes of functions create the basis of several branches of modern mathematics. Those classes appear frequently in investigations conducted in mathematical analysis, operator theory, nonlinear analysis, functional analysis, theories of differential and integral equations, numerical analysis, probability theory, control theory, and so on. Apart from numerous applications, miscellaneous classes of functions are also an object of intensive study in functional analysis, in theory of real functions, and in other important domains of mathematics.

The principal aim of this special issue is to indicate a few directions in the study of some classes of functions and to present results concerning both the theory of the mentioned classes and their numerous applications. We are going to put special emphasis on various possible applications of selected classes of functions.

We invite authors to supply original research as well as review articles treating the considered classes of functions from various points of view and demonstrating their applicability in several branches of mathematics such as the theory of functional, differential, and integral equations and the theory of nonlinear operators, among others. Potential topics include, but are not limited to:

• Functions of bounded variation (classical: Wiener, Waterman, Schramm, etc.)
• Almost periodic functions
• Absolutely continuous functions
• Convex functions and their generalizations
• Other classes of functions and their properties
• Properties of linear and nonlinear operators (superposition, integral, functional integral, integrodifferential, etc.) acting in function spaces

Before submission authors should carefully read over the journal’s Author Guidelines, which are located at http://www.hindawi.com/journals/jfs/guidelines. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/submit/journals/jfs/cfs14/ according to the following timetable: