Question: Which influential rock guitarist co-wrote "Finish What Ya Started" with Sammy Hagar in 1988 and was later named the number one guitarist by "Guitar World" magazine?
Context: "Walk on Water" is a song by American rock singer Eddie Money, from his album "Nothing to Lose" in 1988 and "" in 1989.  Written by one-time Sammy Hagar keyboardist Jesse Harms (who also performed on the track), the tune was released as a single and reached number nine on the "Billboard" Hot 100 and number two on the Mainstream Rock Tracks chart.  It also features a guitar solo from Jimmy Lyon, who had previously been a member of Eddie Money's band. Sammy Hagar is a rock vocalist and guitarist.  Hagar is known as a solo artist and a former member of several notable bands. "Finish What Ya Started" is a song by Van Halen taken from their 1988 album "OU812".  Despite the album being seemingly complete, Eddie Van Halen came up with the riff at 2 in the morning and went down to his then-neighbor Sammy Hagar to show it.  Hagar let Eddie in, and the two played guitars in his balcony until they had a completed song.  Once Eddie left, Hagar decided to write the lyrics despite being late at night.  The theme wound up being unfulfilled sex, summed up by Hagar as "blue balls.  In the song, Eddie Van Halen recorded his guitar part on a Fender Stratocaster plugged direct into the studio mixing console.  The song is one of only two Van Halen tracks featuring Sammy Hagar playing a rhythm guitar part, which he played on a Gibson acoustic. Will Wallner (born 24 January 1987) is an English rock guitarist and songwriter.  His main influences are Ritchie Blackmore, Gary Moore and John Sykes.  He began playing guitar at age 16 and received his first "real guitar", a Gibson Les Paul Custom, which he has played his entire career, at the age of 18.  He began playing guitar by ear, then had taken his first formal guitar lessons from a rock guitar teacher in his home town of Devon, England.  He is an alumnus of the prestigious Colyton Grammar School and a graduate of the University of Portsmouth with a BSc in Music and Sound Technology and has also studied at the Musicians Institute, in Hollywood.  Since 2012 he has been a regular contributor to Guitar World magazine with his weekly blog 'Bent Out of Shape'.  He currently resides in Los Angeles, California and also owns a recording studio in Berlin, Germany. Ronald Douglas Montrose (November 29, 1947 – March 3, 2012) was an American rock guitarist, who led the bands Montrose (1973-77 & 1987) and Gamma (1979-83 & 2000) and also performed and did session work with a variety of musicians, including Van Morrison (1971–72), Herbie Hancock (1971), Beaver & Krause (1971), Boz Scaggs (1971), Edgar Winter (1972 & 1996), Gary Wright (1975), The Beau Brummels (1975), Dan Hartman (1976), Tony Williams (1978), The Neville Brothers (1987), Marc Bonilla (1991 & 1993), Sammy Hagar (1997), and Johnny Winter.  The first "Montrose" album was often cited as "America's answer to Led Zeppelin" and Ronnie Montrose was often referred to as one of the most influential guitarists in American hard rock. Tyler Drew Morris is an American professional guitar player who was born in Boston, Massachusetts.  Morris has performed with Yngwie Malmsteen, Steve Vai, Gary Hoey, Joe Stump, Sammy Hagar, Leslie West, Rudy Sarzo, Vince Neil, Joe Vitale, Johnny Winter, James Montgomery, David Hull, Phil Collen, Fred Coury, Robert Marcello, Kip Winger, AJ Pappas, Jimi Bell, Gary King, George Lynch, Bruce Kulick, Jason Becker, Vernon Reid, Jeff "Skunk" Baxter, Ronnie Montrose and others.  Morris does demonstrations for Fishman Electronics, Dean Guitars, and REVV Amplification among other companies at the annual summer and winter NAMM shows.  At the age of 15, Morris wrote his first studio album, "And So It Begins".  This album was later featured in "Guitar Player Magazine", "Vintage Guitar Magazine", "Heavy Riff Magazine", Korea Guitar, and other worldwide media outlets.  He has performed at venues including Mechanic's Hall, The Larcom Theater, Tupelo Music Hall, The House of Blues in Los Angeles, B. B. King's Blues Club in New York City and in West Palm Beach, The Miami Beach Bandshell, The Regent Theater, The Cutting Room, The Hard Rock Cafe and many other venues all across the United States. The Speed of Sound is a 1988 all-instrumental album by American rock guitarist Ronnie Montrose, who led the bands Montrose (1973-77 & 1987) and Gamma (1979-83 & 2000) and also performed and did session work with a variety of musicians, including Van Morrison (1971–72), Herbie Hancock (1971), Beaver & Krause (1971), Boz Scaggs (1971), Edgar Winter (1972 & 1996), Gary Wright (1975), The Beau Brummels (1975), Dan Hartman (1976), Tony Williams (1978), The Neville Brothers (1987), Marc Bonilla (1991 & 1993), Sammy Hagar (1997), and Johnny Winter.  In 1997, Ronnie stated that this album was his favorite instrumental record he had done so far.  The track titles are words and phrases referencing aviation themes. Vic Johnson is a rock guitarist best known for playing guitar with The BusBoys and later with Sammy Hagar and the Waboritas. "Right Now" is a rock song written by the group Van Halen for their album "For Unlawful Carnal Knowledge".  The song reflects on living for the moment and not being afraid of making a change.  Vocalist Sammy Hagar has said that he was writing the lyrics to this song at the studio very late one night, and he heard Eddie Van Halen in an adjacent room working on a piano melody.  Hagar said he suddenly realized that "we were writing the same song," so he walked into the room and began singing his words over Van Halen's music.  According to Eddie, the instrumental dates back to 1983, "before I wrote "Jump" - it didn't come out until about '92, '93 or something like that, cause nobody wanted anything to do with it."  An early version of the melody appears in the 1984 movie "The Wild Life" which was scored by Eddie Van Halen.  Eddie also stated that before Hagar was hired to replace David Lee Roth, he considered an album that would feature various guest singers, with Joe Cocker assigned to "Right Now". Edward Lodewijk Van Halen (born January 26, 1955) is a Dutch-American musician, songwriter and producer.  He is best known as the lead guitarist, occasional keyboardist and co-founder of the American hard rock band Van Halen and is considered as one of the most influential guitarists in the history of rock music.  In 2011, "Rolling Stone" "Magazine" ranked Van Halen number eight in the list of the 100 Greatest Guitarists.  In 2012, he was voted number one in a "Guitar World" magazine reader's poll for "The 100 Greatest Guitarists of All Time".
Answer: Eddie Van Halen