A prismatic and cylindrical cutting insert for long edge rotary milling applications has multiple indexable cutting edges ranging from four to six or even more depending on the actual milling applications. Each cutting edge of a prismatic or cylindrical cutting insert provides a positive cutting geometry and is equivalent to an indexable cutting edge of a traditional single-sided parallelogram-shaped cutting insert having two indexable cutting edges (often referred as A-Style insert). The prismatic and cylindrical (including tapered or conical) cutting insert may be used for machining a wide range of materials including difficult-to-machine materials, cast-iron and alloys, aluminum and alloys, carbon steels, and fiber reinforced composites.