The Secret Diary of a Knight's Assistant

The individual or group credited with creating the main content of a product, such as a book, film, or other creative work. The value is a free‑text string representing the name(s) of the primary creator.

A unique identifier assigned to books and other printed publications, typically consisting of 10 or 13 digits. It may include hyphens for readability but is treated as a string value. The ISBN uniquely identifies a specific edition of a title across the publishing industry.

The date on which the product was first made available to the public or released for sale. It is expressed as a calendar date in year‑month‑day format (YYYY-MM-DD). This attribute helps users identify the time period of the product’s availability and can be used for sorting, filtering, or determining relevance based on release era.