This book is devoted to some new abstract incorrect problems for polycaloric and bicaloric equations. Incorrect problems for second-order differential equations have been studied in many works by both Soviet and foreign authors. In recent years, incorrect problems for higher-order differential equations have been intensively investigated.Considered in the classical sense, that is, for all the problems under consideration, there is no continuous dependence of the solution on the data. Let us investigate the conditionally correctness, efficiency of various methods of regularization of some new abstract incorrect problems for the bicaloric equation.The paper uses the methods of the theory of conditionally correct problems for differential-operator equations, developed in the works of A.N. Tikhonova, M.M. Lavrent'ev, V.K. Ivanov, Lattes and J. Lyons and others.For specialists in the field of differential equations, doctoral students, senior students, masters specializing in this field