The main place in the book is occupied by the Wiener-Hopf equations .. The most complete theory of discrete and integral Wiener-Hopf equations was built earlier by M. G. Crane . Methods of functional analysis allow us to obtain these results, as well as results on other specific classes of equations in convolutions in one general scheme. This scheme is based on a kind of non-classical operational calculus, the objects of which are functions from unilaterally reversible operators. The second topic of the book is the projection methods for solving equations in convolutions. Methods of functional analysis allow here to build a general scheme. The abstract basis of this scheme is again the mentioned non-classical operational calculus.. Among the considered projection methods, special attention is paid to the Galerkin method and the reduction method. In the final chapter of the book, the results obtained for the scalar case are summarized into systems of equations. For convenience, the presentation begins with theorems on factorization of matrix functions. In addition to the book, the asymptotics of solutions of equations in convolutions . is studied.