The presented work is devoted to development of an electromagnetic tool designed to study electrophysical parameters of sedimentary rocks characterized by macroanisotropic properties. Based on new theoretical and engineering ideas, we have proposed, designed and developed an electromagnetic tool with a high spatial resolution. We have developed complexes of algorithms and computer programs for the analysis of the new electromagnetic logging tool signals in spatially inhomogeneous media. The measured electromagnetic signals and their sensitivity functions to electrophysical parameters of the models are studied. With respect to processing and interpretation of the electromagnetic tool data, we have developed algorithms for filtering, transforming signals into apparent parameters, detecting formation boundaries, and numerical inversion aimed at the determination of the parameters of an isotropic and anisotropic formation, taking into consideration the host medium. We provide examples of the test results obtained in a metrological tank with electrolyte, as well as in natural and artificial freshwater reservoirs. A prototype of the electromagnetic tool was designed and created, with further testing of the prototype and its main components on laboratory test facilities and in conditions close to those in boreholes.