This scientific monograph gives a detailed information about reproduction biology in the grey wolf Canis lupus in Belarus. This topic includes the wolf breeding (mating and denning) behavior, fertility of the species and mortality of its pups. The initial material was not collected occasionally from wolf hunters and wolf pup searchers, but mainly gained by authors first-hand according to a well-set research design and long-term. By analyzing the gathered data, we became convinced that in the wolf reproduction biology there are more exceptions than rules. Therefore, the standard patterns of reproduction biology in wolves that are wide-spread in the published literature about the species we call as common beliefs that are given versus the wolf reality that we have found in Belarus. Concerning the non-standard features in the wolf reproduction biology, we revealed that multiple breeding in wolf pack is a common phenomenon, breeding of yearling females and wolf-dog hybridization were found to be irrespective the food base and strongly depending on the species population density i.e. they are reproduction regulations. Wolf pup mortality was investigated and the crucial role of deliberate predation by lynxes and trampling by wild ungulates on wolf pups survivalship was revealed. Behavioral adaptations of wolf breeders against the reproduction failure were found out.