The eternally prolific V.C. Andrews (she died in 1986 but is still writing new books!) and her Flowers in the Attic series from Pocket Books were staple items on any paperback shelf throughout the 1980s. The cover images became rather iconic and the books themselves were devoured by teenage girls, probably while babysitting. I've never read a word but I can't deny that almost totemic quality of the cover. Classic vintage paperback stuff. Great stepback cover, too - you have to go here and read about its creation.