Traditionally, the Book of Shadows is a spell book used by witches. It is usually a magickal and religious text.
However, as times change and witchcraft evolves, it has become more of a personal journal used by witches to hold thoughts, dreams, and useful spells. The Book of Shadows in contemporary terms is not a tome you can purchase in a store and study. It is generally a collection of spells.
To the left are some notebooks specifically used to create a Book of Shadows, though a witch's Book of Shadows can be a blank-faced notebook, a document on a computer, a three-ring binder, or even a sketch book.