I want to write a book that revolves around a classic song, what do i have to do?

[Mikey]

ok so I have been writing a book that is a literal interpretation of a classic song, and at first i was writing it to just to pass the time but as people have read it they are falling in love with it and are begging me to finish and publish it, my main concern is that it is openly about an old 1969 song and its not as though i'm trying to hide it and make it seem as though the premise was an original idea because at the end the books heroine sings the classic song. My question is are there any one who knows if there are any copyright permission or legal forms i have to deal with before i go on? u can answer me here or email me @ [email protected] thanks alot!