Off with the head!
Makers of very strange-looking electric guitars and basses. Most of their products are headless (they had a single model, the Scepter, that had a headstock) and quite minimalistic, mostly resembling a small oar with a set of strings attached. Their basses came in both 4- and 5-string models, fretted or fretless, and there were 6- 7- and 12-string versions of the guitars. The original Steinbergers were crafted of a composite material consisting of fiberglass, graphite, carbon fiber, Kevlar and epoxy hardener, with phenolic fingerboards (the fingerboards had sonic properties resembling those of ebony -- very good for fretless basses). Eddie Van Halen often played a Steinberger guitar, as did Jeff Mantas of Venom, and many, many others.
So what's with the headless thing? Most electric guitars have their strings attached at the bridge (a piece of metal attached to the guitar's body) on one end. The strings then run the length of the guitar neck, and attach to the head, with each string going into a tuning machine. This is the traditional design, and is basically similar to what you see on classical instruments such as the violin, cello and double bass (yes, I know you tune some of those on both ends, but the concept of having a head is still basically similar, get off my case would you?). A headless guitar is (surprise!) a guitar constructed without the head. It uses special strings that have a ball on both ends, and a locking mechanism at the end of the neck locks the string in place where the head would be. The guitar is tuned using small tuning keys mounted on the bridge that work by pulling on the string directly (instead of using a system of gears and winders like on a traditional guitar). The gearless nature of the headless guitar tuning system means that they don't easily go out of tune. Furthermore, the lack of a head makes it possible to build instruments that are more lightweight, portable and ergonomic. Steinberger guitars' minimalistic body shape and the composite materials used for their manufacture meant that these things were pretty much impossible to destroy or get out of tune, and to my knowledge, Steinberger is unique in the electric instrument industry in that their instruments all have lifetime warranty.
Unfortunately, Steinberger seemed to have a hard time selling instruments because of the strange looks and the high price tags, and they were also late to get into the race of getting endorsement deals with famous musicians. They're the sort of axes you either love or hate with a passion. Steinberger's assets were eventually acquired by Gibson, and most of the original composite models were axed. Today, Gibson is selling "Spirit by Steinberger" models which are all-wood lookalikes of the original Steinbergers with much lower price tags. They do not have the durability or sonic properties of the originals (used original Steinbergers are a favoured item of instrument collectors and Steinberger afecionados), but are still pretty decent instruments, especially considering their extremely low price. Few musicians use them on stage today (because of the so 80's look), but they still see a lot of studio use.
Steinberger is named after Ned Steinberger, who founded the company and invented the Steinberger design as well as much of the special hardware on the instruments. After Gibson acquired the Steinberger company, he founded NS Design, which makes electric classical instruments, like upright basses, violins, cellos and violas. Unlike many instrument manufacturers, Ned Steinberger is an engineer, not a musician, and his strange designs reflect his often-stated view that a musical instrument is a tool, not a fashion statement.