The music was discovered on at least 30 cassettes Gaye recorded as demos in Belgium. And some of them are said to be so good, they could even be hits today.
 
"Each time a new instrumental started when Marvin started singing, I gave it a number," [lawyer Alex Trappeniers] told the BBC. "At the end when I had listened to all the 30 tapes I had 66 demos of new songs. A few of them are complete and a few of them are as good as Sexual Healing, because it was made in the same time."
 
One new track above the others makes Alex think we might hear another global hit from Marvin Gaye in the future - just think of the way in which relatively primitive recordings of the Beatles were salvaged and remastered to create their final hit Now and Then.”
 
The question now is whether the quality is good enough to use after all these years and who actually owns the recordings. Until those issues are settled, we may hear a lot more talk in court than songs on the radio. But the fact there could be "new" Marvin Gaye music all these years later is incredible. 

Marvin Gaye: Never-before heard music resurfaces in Belgium