The Kapoor family is perhaps the largest family in the Indian film industry. To make sure you have all the links right, check out the family tree on the web home of RK Films.

RK films have always (well, almost always) been associated with great music. Yet, no matter who the music director, the music for an R.K. film was always Raj Kapoor's. His collaborators were only channels of his expressions. Here's a good article on the musical legacy of Raj Kapoor.