Short answers, pulled from the story.
Norwegian Wood is John Lennon's veiled account of an extramarital affair he had in London. The title refers to the cheap pine wall panelling fashionable in London at the time, which Paul McCartney described as an ironic detail. The song's final verse, in which something burns, was explained by McCartney as the protagonist's act of revenge.
George Harrison played the double-tracked sitar on Norwegian Wood, marking the first appearance of the Indian string instrument on a Western rock recording. Harrison first encountered a sitar on the set of Help! at Twickenham Film Studios in April 1965, and his interest deepened after a conversation with David Crosby of the Byrds on the 25th of August 1965. Lennon asked Harrison to add the sitar part during the recording sessions.
The Beatles began recording Norwegian Wood on the 12th of October 1965 at EMI Studios in London, returning on the 21st of October to record the master take. The song was released on Rubber Soul on the 3rd of December 1965, and reached number 1 in Australia in May 1966 when issued as a single coupled with Nowhere Man.
Norwegian Wood is widely identified as the first example of raga rock and is credited with sparking widespread use of Indian instrumentation in Western rock. Brian Jones of the Rolling Stones added sitar to Paint It Black after the song's influence; Donovan's Sunshine Superman, the Yardbirds' Shapes of Things, and the Byrds' Eight Miles High all reflected the same trend. The song also helped elevate Ravi Shankar and Indian classical music to mainstream popularity in the West.
Rolling Stone magazine ranked Norwegian Wood at number 83 on its 2004 list of The 500 Greatest Songs of All Time. In 2006, Mojo placed it at number 19 in its list of The 101 Greatest Beatles Songs, compiled by a panel of music critics and musicians.
According to author Jonathan Gould, Norwegian Wood transformed Ravi Shankar's career by bringing Indian classical music to mainstream Western audiences. Shankar later wrote of first becoming aware of a great sitar explosion in popular music during the spring of 1966. George Harrison met Shankar in London in June 1966 and became his student, deepening a relationship that shaped Harrison's music through his work on Sgt. Pepper's Lonely Hearts Club Band and beyond.