Signatories to the Berne Convention must protect materials for a minimum of 50 years after the death of the creator; some countries, such as the United States, have increased this to 70 years.
"Celebration" will be protected by copyright until 70 years after the death of the last surviving co-author, of which there are 10.
Generally, at least under US Law, copyright protection extends 70 years past the death ot the author/creator of the work.
The copyright of a work lasts the life of the author plus 50 years from the end of the calendar year of death. If there is more than one author, the above rule applies to the last author to die.
New works are protected for the life of the author plus 50 years in most countries (the US has extended this to 70 years).
In Great Britain copyright in literary, dramatic, musical and artistic works expires 70 years after the death of the author. Where the work has more than one author, the copyright expires 70 years after the death of the last surviving author. The publisher's copyright for the typographical arrangement of a published work is 25 years from the end of the year in which that publication occurred. This protects a publisher's copyright in all types printed works including books, magazines, newspapers, and any other periodicals. this is commonly applied to recordings and video as well.
An anonymous work that is registered with the US Copyright office will receive the same protection as as any other work. It's duration will vary depending on if the author reveals and verifies his or her identity. It the author remains anonymous, the duration will last 95 years from the initial publication or 120 years from the creation of the work according to 17 U.S.C §302(c). If the author does reveal and verify their identity the copyright duration will be the life of the author plus 70 years.
Under current US law life of the author +70 years or in the case of work-for-hire 95 years post publication
A million trillion years baby.
95 years from creation.
Copyright term for software in India is 60 years from the date of publication.
Generally 95 years from the date of publication, in the USA, less or more if created and published in other countries (i.e., 50 to 70 years after death of the author).
You would need to know when and where it was first published, by whom, what nationality, his or her nation of domicile, and whether the publication adhered to the necessary formalities at the time of publication (e.g., copyright notice, registration, renewal), if any. For example, books published in the USA by a US author prior to 1923 is public domain, the copyright having expired no later than 1978. A book published by a US author in the US, with copyright notice and renewal after 1922 and before 1978 would be copyrighted for 95 years. After that it would most likely be 95 years unless the author was independent (not employed as an author), in which case it would last 70 years after the year of the author's death.