Abstract: A booster for high efficiency initiation of an explosive material comprising a body portion having substantially tapered sides and a substantially flat interface surface at the larger end of the body portion extending generally laterally thereof for contacting the explosive material. A plurality of passageways may be formed in the booster to receive a means for detonating same. When compared with traditional cylindrical boosters of either equal weight or equally sized interface surfaces, the disclosed booster resulted in shorter run-up distance and a more effective release of explosive energy. Although numerous geometric configurations of the booster are disclosed, a presently preferred embodiment thereof takes the shape of a conical frustum, the larger planar surface of which is to be oriented as the interface surface toward the explosive material to be detonated.