The review analyzes the physical mechanisms of energy dissipation in type-II superconducting alloys in the mixed state. A very simple microscopic theory is presented for the dissipative processes in alloys with paramagnetic impurities. The main premises of the microscopic theory are described and its results are presented for the resistivity in the case of ordinary alloys (without paramagnetic impurities) in weak magnetic fields smaller than the upper critical field, at the low temperatures and at temperatures close to critical, and also in the case of strong magnetic fields, on the order of the upper critical field, in the entire temperature interval. The theory is compared with experiment.