Jackson is a guitar manufacturer originally owned and operated by Grover Jackson, a partner of Wayne Charvel of Charvel Guitar Repair. It is probably best-known for its "Rhoads" V model guitar, originally designed and used by guitarist Randy Rhoads. This model inspired Grover to start the Jackson guitar company.
Wayne Charvel sold his interest in the Charvel name to Grover Jackson November 10,1978. The shop was located in San Dimas, California and manufactured guitars in this location from 1979 to 1986, when the Company merged with IMC (International Music Corporation) a Texas based importer of musical instruments.
Recently, rights to the Charvel name and permission to manufacture Charvel guitars was granted to the Fender Guitar Company. Fender is now manufacturing guitars that are almost exactly like the original San Dimas Charvels, save for a few details. In some cases the guitars are even being built from NOS Charvel parts.
Jackson Guitars has become most famous for its slender and elegant models, often with an aggressive look popular with harder rock and metal music and are known for their fast playing necks. This made them particuarly popular among extreme metal guitarists in the 80's and early 90's (see artists list).
Almost all Jackson (and many Charvel) guitars share the typical pointed, roughly triangular headstock, which is simply a Gibson Explorer style headstock modified to avoid lawsuits. Charvel/Jackson was the target of many copyright lawsuits from Gibson and Fender which led to using the modified Explorer headstock. This also ended using Stratocaster styled headstocks for Charvel guitars. Various models, however (especially a good number of Dinkys) do have a reversed headstock with the tip pointing upwards.