  Almost-complex and hyper-complex manifolds are considered in this paper from
the point of view of complex analysis and potential theory. The idea of
holomorphic coordinates on an almost-complex manifold $(M,\mathbf{J}%)$ is
suggested by D. Spencer. For hypercomplex manifolds we introduce the notion of
hyper-holomorphic function and develop some analogous statements. Elliptic
equations are developed in a different way than D. Spencer. In general here we
describe only the formal aspect of the developed theory.
