The bass guitar (also called electric bass, or simply bass;  /ˈbeɪs/) is a stringed instrument played primarily with the fingers or thumb (by fingering, slapping, popping, tapping, or thumping), or by using a pick.

The bass guitar is similar in appearance and construction to an electric guitar, but with a longer neck and scale length, and four, five, six, or eight strings. The four-string bass—by far the most common—is usually tuned the same as the double bass, which corresponds to pitches one octave lower than the four lower strings of a guitar (E, A, D, and G). The bass guitar is a transposing instrument, as it is notated in bass clef an octave higher than it sounds (as is the double bass) to avoid excessive ledger lines. Like the electric guitar, the bass guitar is plugged into an amplifier and speaker for live performances.

Since the 1960s, the bass guitar has largely replaced the double bass in popular music as the bass instrument in the rhythm section. While the types of basslines performed by the bassist vary widely from one style of music to another, the bassist fulfills a similar role in most types of music: anchoring the harmonic framework and laying down the beat. The bass guitar is used in many styles of music including rock, metal, pop, punk rock, country, reggae, blues, and jazz. It is used as a soloing instrument in jazz, fusion, Latin, funk, and in some rock and metal styles.

Robbie Merrill (born June 13, 1963 in Lawrence, Massachusetts) is an American bass guitar player, best known for his work with the heavy metal band Godsmack.

Robbie was one of the founding members of Godsmack, meeting Sully Erna through Sully's sister they became roommates and friends. In February 1995, Erna decided to start a new band as the lead singer after playing the drums for more than 23 years. His new band The Scam formed with Erna on vocals, Robbie Merrill on bass, local guitarist and friend Lee Richards on guitar, and Tommy Stewart on drums. The Scam quickly changed its name to Godsmack, after recording one demo.

Robbie is also a founding member of the band Another Animal along with Shannon Larkin, Tony Rombola, Lee Richards, and Whitfield Crane. Excluding Whit Crane all have been members of Godsmack presently or in the past.

Merrill was featured in the IMV "Behind The Player" DVD series, in his DVD he gives an intimate behind-the scenes look at his life as a musician, he then gives in-depth lessons for how to play Speak and Voodoo by Godsmack on bass and jams the tracks with Godsmack drummer Shannon Larkin.

Geoffrey Arnold "Jeff" Beck (born 24 June 1944) is an English rock guitarist. He is one of three noted guitarists to have played with The Yardbirds (Eric Clapton and Jimmy Page are the other two). Beck also formed The Jeff Beck Group and Beck, Bogert & Appice.

Much of Beck's recorded output has been instrumental, with a focus on innovative sound and his releases have spanned genres ranging from blues-rock, heavy metal, jazz fusion and an additional blend of guitar-rock and electronica. Although he recorded two hit albums (in 1975 and 1976) as a solo act, Beck has not established or maintained the sustained commercial success of many of his contemporaries and bandmates. Beck appears on albums by Mick Jagger, Kate Bush, Roger Waters, Donovan, Stevie Wonder, Les Paul, Zucchero, Cyndi Lauper, Brian May and ZZ Top. In 1988, he made a cameo appearance in the movie Twins.

He was ranked 5th in Rolling Stone's list of the "100 Greatest Guitarists of All Time" and the magazine has described him as "one of the most influential lead guitarists in rock".MSNBC has called him a "guitarist's guitarist". Beck has earned wide critical praise and received the Grammy Award for Best Rock Instrumental Performance six times and Grammy Award for Best Pop Instrumental Performance once. He has been inducted into the Rock and Roll Hall of Fame twice: as a member of The Yardbirds (1992) and as a solo artist (2009).

Leslie Edward "Les" Claypool (born September 29, 1963) is an American musician and writer, best known as the lead vocalist and bassist in the band Primus. Claypool's playing style on the electric bass mixes tapping, flamenco-like strumming, whammy bar bends and slapping.

Claypool has also self produced and engineered his solo releases from his own studio "Rancho Relaxo". 2006 saw the release of a full-length feature film Electric Apricot written and directed by Claypool as well as a debut novel South of the Pumphouse.

Claypool was born September 29, 1963 in Richmond, California, but was raised in El Sobrante, California in a working class family with a history of working as auto mechanics. A close family friend, Rhys Hickman, taught him the basics of the slap bass technique, which he mastered throughout his educational period. His early education included Collins Elementary School and De Anza High School, where he was a personal friend of Kirk Hammett.

In 1986, after the death of Metallica bassist Cliff Burton, school friend Kirk Hammett encouraged Claypool to audition for Metallica as Burton's successor. In Metallica's Behind the Music, Claypool said that he jokingly asked the others if they wanted to "jam on some Isley Brothers tunes" during the audition, a reference to his little experience of the thrash metal scene. James Hetfield remarked that Claypool was not awarded the job because "he was too good" and "should do his own thing." Claypool would later admit that he wouldn't have fit in with the band and "would've looked like a freak". The bass slot was instead given to Jason Newsted, who played with Metallica until his departure in 2001. For several years before forming Primus, Claypool worked as a carpenter in El Sobrante. Claypool has cited Larry Graham, Chris Squire, Tony Levin, Geddy Lee, Paul McCartney, Geezer Butler, Bootsy Collins, Stanley Clarke, John Paul Jones, and Sting as his musical influences.

John Francis Anthony Pastorius III (December 1, 1951 – September 21, 1987), known as Jaco Pastorius, was an American jazz musician, composer, and electric bass player.

His playing style was noteworthy for containing intricate solos in the higher register and for the "singing" quality he achieved on the fretless bass. His innovations also included the use of harmonics. Pastorius suffered from mental illness including a substance-related disorder, and was diagnosed with bipolar disorder in 1982. He died in 1987 at age 35 following a violent altercation at a Fort Lauderdale bar.

Pastorius was inducted into the Down Beat Jazz Hall of Fame in 1988, one of only six bassists to be so honored (and the only electric bass guitarist). He is one of the most influential electric bass players of all time.

John Francis Pastorius III was born December 1, 1951 in Norristown, Pennsylvania to Jack Pastorius (big band singer and drummer) and Stephanie Katherine Haapala Pastorius, the first of their three children, Jaco Pastorius was of Finnish, German, Swedish and Irish ancestry.