While Paul Tutmarc originally invented the solidbody electric bass way back in 1935, it wasn't until Leo Fender released the Fender Precision Bass in 1951 that the world had its first commercially successful electric bass. In the late 1940s, the bass player in most musical groups used a double or "upright" bass. Unless they wanted to use a tuba, there was little else available to most players. One of the problems that musicians were encountering was the inability for their bass parts to be heard over the sound of the amplified guitars, horn sections and drummers. Electric pickups added to double bass instruments could only do so much before suffering from feedback. Fender sought to change all that by creating a solid body electric bass that could be amplified the same way as his new Telecaster guitar. Rather than use the more difficult to play fretless design of an upright bass, the design that Leo Fender and employee George Fullerton created featured a fretted neck, so that notes could be played "with precision" -- giving even guitarists the ability to "double" on bass and still play with accurate intonation, and giving Fender's bass its name - the Precision Bass. Other advantages of the design included the greatly reduced size and bulk, making it far easier to transport from gig to gig, and due to the solid body design, a much greater resistance to feedback.
The Precision Bass is often fondly referred to as the "P Bass." The earliest models had a slab double-cutaway body without the "tummy" and forearm contours that were added to the instrument in 1957. The design of the double cutaway and "horns" was influenced by a desire to make the bass balance well when hanging from a strap. The early P Basses also featured a simple single coil pickup, and one volume control and one tone control mounted on a small metal control plate. The controls remained the same after 1957, but the pickup was changed to a split coil humbucking model at that time, and the entire model received a series of cosmetic upgrades. The peg head was reshaped to more closely match the design of the Stratocaster, as opposed to the more Telecaster influenced shape of the originals. The design and shape of the pickguard was also changed, and the controls were mounted directly to it, instead of to a separate control plate.
The popularity of the Precision Bass, and later, the Fender Jazz Bass models was so widespread that many musicians, producers and band leaders referred to any electric bass as a "Fender Bass" -- using it as an almost generic term throughout the 1950s and even well into the 1970s. Today, Fender offers a variety of different models that have expanded the range and tonal capabilities of the instrument, including five string models, instruments with active electronics and a second pickup.