Can I use "Fifty Shades of ..." as the title of my book?
We would like to name a book about lifehacking in reference to the film and book, "Fifty Shades of Grey".
The book will, of course, be called slightly differently and it will not be a fiction novel, but a guide book.
The title we intend is "Fifty shades of something" or "50 shades of something" if, for example, the name with
numbers would be safer. It will be published as an ebook in Apple Store, Google Store, Kobo Store and Amazon Store
Would such name be legally risky in the US and in other English-speaking countries such as:
Canada, UK, Australia, New Zealand etc.? Or would it be 100 percent safe?