I'd do:
create a new model to store custom information and decorate the product to has_one :book_info, or something, and another model to store author information, then extend solidus searcher to include this information
Another one with pure solidus:
Create a taxonomy Authors, the real authors as taxons, then add this taxon to products, and use product properties to specify extra information such as ISBN, etc. you will still need to customize product searcher to include taxon and product properties