This volume deals with first and second order complex equations of hyperbolic and mixed types. Various general boundary value problems for linear and quasilinear complex equations are investigated in detail. To obtain results for complex equations of mixed types, some discontinuous boundary value problems for elliptic complex equations are discussed. Mixed complex equations are included in the quasilinear case, and the text considers both boundary value conditions in the general oblique derivative case and multiply connected domains. Complex analytical methods are used to investigate various problems as well. In particular, hyperbolic numbers and hyperbolic complex functions are introduced to handle hyperbolic complex equations. Researchers and graduate students in mathematical analysis will find this text indispensable.