In these writ petitions seeking the issue of appropriate writs, the validity of certain assessment to sale, tax made by the Sales Tax Authorities and the steps taken by them to revise assessments already made are brought into question. The case is somewhat out of the ordinary and to start with the following facts may be stated. The petitioner is a film producer, being the sole proprietor of Messrs. A. V. M. Productions. In or about 1962, the petitioner obtained the copyright of a story in Hindi entitled Pooja ke Phool and on the basis of that story, he produced a cinematograph film. In 1964, a Hindi version of a popular Tamil picture was also produced. The petitioner entered into an agreement with Messrs. A.V.M. Limited whereunder the petitioner leased to the latter entity the right to exploit the cinematograph film Pooja ke Phool for a period of 49 years on certain terms, which will be referred to in detail later. In respect of the second film, a similar agreement of lease was entered into in August, 1963, with Messrs. Murugan Brothers and this lease comprised 1/20th of the rights of the petitioner. Later by another agreement, a lease of 10/20th of the rights in tha