“Written by Dexter Wansel, Cynthia Biggs, and Kenneth Gamble, ‘If Only You Knew’ became the Patti Labelle’s first #1 R&B hit as a solo artist,” (Songfacts). “Wansel – who also collaborated with Biggs on the track ‘Shoot Him On Sight’ from LaBelle’s previous album, The Spirit’s In It – didn’t think the mid-tempo ballad was that great, but LaBelle disagreed. ‘She loved it from the very beginning and saw the potential, that there were a lot of lonely people out there who loved other people and didn’t really know how to say it,’ he recalled in The Billboard Book Of Number One R&B Hits. ‘She felt like she could say it for them.’
LaBelle found fame as the leader of the progressive soul trio Labelle, who had a big hit with ‘Lady Marmalade’ in 1974. Following their split a couple years later, she worked hard to build a solo career that earned her critical acclaim, but she struggled to make the charts. After releasing her first four albums with Epic, LaBelle signed with Philadelphia International Records, pinning her hopes for a hit on the label’s founders, Kenneth Gamble and Leon Huff. The songwriting and production duo was behind many of the hottest soul singles of the ’70s, including ‘If You Don’t Know Me By Now,’ ‘Love Train,’ and ‘Me and Mrs. Jones.’ Her first album with PIR didn’t yield any hits, but she finally scored on I’m In Love Again (1983). Aside from being her first R&B chart-topper, “If Only You Knew” was her first solo crossover hit, peaking at #46 on the Hot 100.” The track also climbed all the way to #1 on the Cash Box US Black Contemporary Singles chart.
The intro is in E major, but there’s an early shift to C# major when the verse starts at 0:29. The chorus (0:58) returns to E major; the alternating pattern continues throughout.