Songfacts®:

• Paul Anka had a hit in 1959 with "Put Your Head On My Shoulder," where he implores a girl to do as the title suggests so he can move in for the kiss. This song has a similar, but more intimate sentiment, with Brian Wilson asking the girl for a quiet moment so he can hear her heartbeat. That's much better than talking.
• Brian Wilson wrote this song with Tony Asher, his lyricist on most of the Pet Sounds tracks. Asher explained in the liner notes to the 1999 Pet Sounds reissue: "It's an interesting notion to sit down and try and write a lyric about not talking. That came out of one of those conversations where [Brian and I] were talking about dating experiences... I think at some point we were talking about how wonderful non-verbal communication can be between people."
• Brian Wilson, who sang the lead vocal, is the only Beach Boy to perform on this track. The other musicians were some of the elite West Coast players that often augmented the group in the studio. Research done for various reissues of Pet Sounds using the musician's union contracts reveals these players at the session, although it's hard to tell whose playing made it into the final mix:
  
  Glen Campbell, Billy Strange - guitar
  Hal Blaine - drums
  Carol Kaye - electric bass
  Lyle Ritz - string bass
  Frank Capp - vibraphone, tympani
  Steve Douglas - percussion
  Al de Lory - organ
  
  This session took place February 11, 1966 at Western Recorders in Hollywood. A session for strings, which were overdubbed onto the track, was done at the same studio on April 3, 1966. Players listed:
  
  Arnold Belnick, Ralph Schaeffer, Sid Sharp, Tibor Zelig - violin
  Norman Botnick - viola
  Joseph Saxon - cello
  
  If guitars did make it onto the track, they're mixed very low. The bass is a lot more prominent, simulating a heartbeat in parts.
• Musically, this is a very complex and unconventional track that many composers hold in very high esteem. Tony Banks of Genesis cites it as the song he spent the most time deconstructing. "When it came out, there had been nothing quite like it in terms of the sort of harmonies it was using," he said in a Songfacts interview. "It doesn't sound as complicated as all that but it just goes through all these key changes as it goes along. To me, it's just such a wonderful construction and beautiful piece of music."
• The Swedish singer Anne Sofie von Otter released a version of this song on her 2001 album For the Stars that was produced by Elvis Costello.