Salim Khan, one of the co-writers of Don feels Amitabh has grown over the years and become the best in the industry. He feels Amitabh's first tryst with comedy was Don. People believe it was Amar Akbar Anthony because of its early release but it is actually Don. Don got delayed because the producer of the film, Nariman Irani died during the filming of the movie.
Salim Khan was a top writer and his pair with Javed Akhtar was paid higher than many lead actors of that time. When Nariman Irani approached them for Don, they were already working on top projects. Nariman Irani was always observed by Salim Khan who used to watch him from his terrace window as he used to come to Waheeda Rehman's house very often as they both were doing a film together. It was sometime then when Nariman asked Javed Akhtar to write a film for them and that was when the seeds of Don were sown.
Since Salim and Javed were a top pair then, they could not compromise on what they write. They needed something out of the box especially after Seeta Aur Geeta and Sholay. They had to keep in mind that they could not repeat themselves. Being inspired from a few films, they wrote the classic Don.
But Salim Khan owes the song Khaike Paan Banaraswala to Manoj Kumar. Why Manoj Kumar we wonder? Well Salim Khan says that when Don's first copy was out, they decided to show the film to Manoj Kumar. Manoj though impressed with the film, felt that the second half was very fast and needed some kind of a break. Even Salim-Javed felt that it was a valid point that he made. So they decided to incorporate the song Khaike Paan Banaraswala. And rest is as we say is HISTORY. The song became an overnight chartbuster. Salim-Javed had the distribution rights of Indore and Bhopal, and thanks to the popularity of the song at those centers, they were bathing in money that came from that territory.
It is sad that Nariman Irani never got to see the light of the day of the released Don due to his ill fated freak accident on the sets of Don, but if he was alive, he would have been proud of the product he had made.
And yes, lest we forget, Don is a remake of an English classic film House OF Secrets. Who says inspiration never existed then!!!!!