Short answers, pulled from the story.
John Lennon and Paul McCartney wrote the song during late 1963 in the basement music room of 57 Wimpole Street. They worked on the track eyeball to eyeball while Jane Asher hosted the session for her parents.
The Beatles recorded the single at EMI Studios in London on the 17th of October 1963. George Martin mixed both mono and stereo versions on the 21st of October 1963 using four-track recording equipment.
I Want to Hold Your Hand remained at number one for five consecutive weeks after dislodging She Loves You from the top spot. It became the Christmas number one of 1963 and stayed within the UK top 50 for twenty-one weeks total.
Capitol Records released the record in America two weeks ahead of schedule following pressure from Brian Epstein. DJ Carroll James played the record on the 26th of December 1963, leading to a Billboard Hot 100 entry by the 18th of January 1964.
The Recording Industry Association of America named the single one of the Songs of the Century while the National Endowment for the Arts also recognized its importance. The song entered the Grammy Hall of Fame in 1998 and appeared on The Rock and Roll Hall of Fame list of 500 Songs That Shaped Rock and Roll.