Short answers, pulled from the story.
"Within You Without You" was written by George Harrison, the Beatles' lead guitarist. It was inspired by a dinner conversation at Klaus Voormann's home in Hampstead about the metaphysical space separating people, and by Harrison's stay in India in September-October 1966, during which he studied the sitar under Ravi Shankar and absorbed Hindu philosophical texts.
The recording features sitar, tambura, dilruba, tabla, and swarmandal. The dilruba is a bow-played string instrument; the swarmandal is an Indian zither or harp that Harrison played himself to provide the glissando flourishes in the alap. Indian musicians from the Asian Music Circle in north London performed alongside Harrison and Beatles aide Neil Aspinall.
The basic track was recorded on the 15th of March 1967 at EMI's Abbey Road studio 2 in London. Overdub sessions followed on the 22nd of March and the 3rd of April. The song was produced by George Martin, who arranged the string parts for eight violins and three cellos, performed by members of the London Symphony Orchestra.
"Within You Without You" appears on the Beatles' 1967 album Sgt. Pepper's Lonely Hearts Club Band, released on the 26th of May 1967. It was sequenced as the opening track on side two of the LP.
The lyrics convey tenets of Vedanta philosophy, including maya (the illusory nature of existence), advait (the one essential reality), and satya (perception of truth). Harrison also quotes from the gospels of St Matthew and St Mark in the final verse, warning against gaining the world at the cost of one's soul.
Cover versions have been recorded by Sonic Youth, Rainer Ptacek, Oasis, Patti Smith, Cheap Trick, the Flaming Lips, the Soulful Strings, Big Daddy, Easy Star All-Stars, and Big Head Todd and the Monsters, among others. Sonic Youth's 1988 recording, made for an NME tribute album, was ranked number 2 on Vulture's list of their ten favourite Beatles covers.