In the Wee Small Hours is the ninth studio album by American vocalist Frank Sinatra. It was released in April 1955 on Capitol Records, produced by Voyle Gilmore with arrangements by Nelson Riddle. The songs on the album deal with themes such as loneliness, introspection, lost love, failed relationships, depression and night-life. As a result, In the Wee Small Hours is generally regarded as one of the first concept albums. The album's cover artwork reflects these themes and portrays a reflective-looking Sinatra on an eerie and deserted street awash in blue-tinged street lights. , Sinatra would successfully continue the "concept" formula with later albums such as Songs for Swingin' Lovers! and Only the Lonely. He had been developing the idea since 1946 with his first album release, The Voice. In the Wee Small Hours was issued as two 10-inch LP discs, and also as one 12-inch record LP, making it one of the first of its kind. It was also issued as four four–song 45-rpm EP discs sold in cardboard sleeves with the same cover as the LPs, not in paper covers like 45-rpm singles. (See Gramophone records for explanations of these terms.)
The album was a commercial success, reaching number 2 on the US charts where it stayed for 18 weeks, being Sinatra's highest charting album since his 1947 release Songs by Sinatra. As of 2002 it has been certified Gold by the RIAA, selling over 500,000 units. The album was also a critical success, and is listed as the third most acclaimed album of the 50s. Rolling Stone called it the 101st greatest album of all time.