Preface Constructing nonlinear parameter-dependent mathematical models is essential in modeling in many scientific research fields. The investigation of branching (bifurcating) solutions of such equations is one of the most important aspects in the analysis of such models. The foundations of the theory of bifurca tions for the functional equations were laid in the well known publications by AM. Lyapunov (1906) 1, vol. 4] (on equilibrium forms of rotating liq uids) and E. Schmidt (1908) 1]. The approach proposed by them has been throughly developed and is presently known as the...