Thanks to movies and TV shows, most b people have heard of books of shadows. In most of these sources, these books have been in the family for generations and are either filled with spells or herbology. These are partially correct.
There are two types of Books of Shadows. One is more informational and contains spells, symbols, and rituals. The other is more of a journal detailing various aspects of Paganism in your life, how certain spells worked, or Sabbat and Esbat traditions. Most people keep a personal Book of Shadows, but many groups keep one for the group as well. Either way, it doesn’t have to be fancy with calligraphy and illustrations. The first collection of rituals I wrote is in a tiny binder. Anyway, this personal Book of Shadows is more journal than anything. I will probably include those rituals I wrote long ago eventually.