The "Penumbra Moon" album started life on 8th September 1978 at  Eel Pie Studios in Twickenham where two tracks: "Give Me Love" and "Old Jealousy" were recorded.

"Penumbra Moon", "Love Finds You", "Warrior" and "White City Lights" were also recorded there at around the same time, while "Alone Again" came much later. "Brown And Beige", "That Other Guy" and "Velvet Rut" were recorded at Eel Pie Studios in Broadwick Street, London, engineered by Mike Pela.

"Reverie", the most recent track, was recorded at home in 1996, with the help of his son, Morgan. It was his idea to transfer all the tracks from the original multi-track masters to ProTools and to work on them at A Major Studio in Shepherds Bush. Under Billy's direction; Morgan and Phil Chapman created new arrangements and updated the tracks to complement the original instrumentation.

Three tracks on this album were co-written with Billy's brother, Michael and one with Jon Lind. Musicians include: Alan Murphy, George Butler, Richard Bailey, Phil Chen, Kenny Altman, John (Rabbit) Brundrick, Tony Butler, Mark Brzezicki, and Morgan.