We obtain a constructive description of monogenic functions taking values in a finite-dimensional semi-simple commutative algebra by means of holomorphic functions of the complex variable. We prove that the mentioned monogenic functions have the Gateaux derivatives of all orders. For monogenic functions we prove also analogues of classical integral theorems of the holomorphic function theory: the Cauchy integral theorems for surface and curvilinear integrals, the Morera theorem and the Cauchy integral formula.Introduction. William Hamilton (1843) constructed an algebra of noncommutative quaternions over the field of real numbers R, and developing the hypercomplex analysis began. C. Segre [1] constructed an algebra of commutative quaternions {x + iy + jz + kt : i 2 = j 2 = −1, ij = k, x, y, z, t ∈ R} over the field R that can be considered as a two-dimensional commutative semi-simple algebra of bicomplex numbers {z 1 + jz 2 : j 2 = −1, z 1 , z 2 ∈ C} over the field of complex numbers C.A theory of functions of a bicomplex variable was developed in papers of many authors (see, e.g., [2,3,4,5,6]). In particular, in the papers of F. Ringleb [2] and J. Riley [3], it is proved that any analytic function of a bicomplex variable can be constructed with an use of two holomorphic functions of complex variables. In addition, G. Price [4] considered multicomplex