In an interview with Songfacts, [co-songwriter] Will Jennings said: “Valerie is a real person, whose identity I will not reveal. She was almost at the top of the world in her profession and let it slip away from her. She was a dear friend and this was my tribute to her.”[1] It has been alleged, however, that he was thinking about singer Valerie Carter.[2]

https://en.wikipedia.org/wiki/Valerie_(Steve_Winwood_song)

The synth solo on this is solid. Check out this guy reproducing it: https://yewtu.be/watch?v=tzQHsYWANSE