The double bass (contrabass, upright bass, string bass, violone) is a large string instrument of three, four, or five strings, made of wood, and played with a bow (arco) or plucked with the fingers (pizzicato). Unique among orchestral string instruments, it shares a history with both viol and violin instrument families. Today it is commonly tuned in fourths with four (E’-A’-D-G) or five (B’/C’-E’-A’-D-G) strings. Other historical tunings include a three-string instrument tuned in fifths (A’-D-G), a four- or five-string “Viennese tuning” (typically F’-A’-D-F#-A, with lowest string optional), and five- and six-string violone tunings: in G (G’-C-F-a-d-g), in A (A’-D-G-b-e-a), or in D (D’-G’-C-E-A-d). It is the only orchestral string instrument with two types of bows—the “overhand” French bow (violin family) and the “underhand” German bow (viol family)—and is the only transposing orchestral string instrument: music is usually notated an octave above sounding pitch (hence the name, double bass, for the instrument’s role in orchestral textures of doubling the violoncello part an octave lower than written). Violones began as the bass voice in viol consorts and realized continuo lines in church, orchestral, and operatic genres. A rich culture of solo and chamber music for a double bass instrument, known today as the Viennese violone, reached a peak of technical virtuosity throughout territories influenced by the Habsburgs between approximately 1750 and the first decade of the 19th century. Other virtuosi, like Domenico Dragonetti and Giovanni Bottesini, both of whom played three-string instruments tuned in fourths, followed in the 19th century. National schools of orchestral playing emerged across Europe in the 19th and 20th centuries alongside the development of the modern orchestra and conservatories. Double bass sections serve essential functions in the orchestra: they add weight, provide dynamic power, reinforce the rhythmic foundation, and shape musical phrases. The 20th century saw a renaissance of double bass virtuosi who inspired the composition of new chamber and solo works for the instrument. In the late 19th century, the double bass also became a common fixture in American ragtime and string bands. The string bass has always served in a supporting role in military and concert bands. It has also maintained a central role in jazz styles since the 1920s, and from the 1940s to the 1960s it was common in American popular musical genres such as country, bluegrass, western swing, rock ’n’ roll, and rockabilly.