As discussed fully in the copyright section of this site, OIF does not own the copyrights to any of Osho’s books. The documents Osho allegedly signed were at most licenses for publishing rights for not more than eight books . Further, according to those documents any future discourses Osho gave were not to be part of the license unless Osho specifically gave them to the licensee. He had the option of refusing to give any future work. There is no evidence that Osho ever included more than eight books in the license. Since there is no original of the license document, not even the license for eight books can be proven in court.
The most OIF, Zurich could possibly own (if the document could ever be authenticated) would be an exclusive right to publish the material included in the eight books listed. Further, there’s no evidence that OIF owned rights other than those belonging to Osho in the books.
Since Osho didn’t write books, but gave discourses that had to be transcribed, edited, designed, and so on, many people besides Osho were involved in creating the books. Each of those persons whose contribution was copyrightable owned the rights to their own works unless they had specifically given those rights away. Whether or not transcribing, editing, designing, and so on created a copyright interest in the work depends on the law of the country where the work was done. In the same way, the sufficiency of any assignment of rights depends on the law of that country. For example, in the US work-for-hire agreements must be in writing and signed before the work is completed in order to be legally enforceable.
Given the nature of Osho’s work and the way books were created, it would be virtually impossible for anyone to own all the rights in one book, let alone all the books. They could start from scratch and do the transcribing and editing over again, but the cost of that would probably be prohibitive.
OIF, Zurich's claim to own exclusive rights in all of Osho’s books is without foundation and can never be proved.