Every Witch when they are beginning to learn their personal path of The Craft or The Old Ways either through reading, a mentor, or a coven leader are told to make or buy a journal of some type. This journal becomes one of their magickal tools that is commonly called by one of two names either a Book of Shadows (BOS) or a Grimoire which is a very personal and Important book as well as a magickal tool.
Let me regress here for a moment thanks to how witches are usually stereotyped through different type of media outlets a BOS would belong to a good witch and a Grimoire to a dark witch, daemon, or another evil being.
Actually many witches including myself use the titles interchangeably. While others in a coven of witches or are a solitary practitioner, use the title BOS as their very personal secret book for their eyes only magical journal. The title Grimoire on the other hand is usually used in a coven for their coven’s magickal journal and is often written in and/read by many different people as it belongs to the past, present, and future coven members and can be read by those at a specific level of learning on up and full imitation into the coven. While solitary practice their BOS or Grimoire belongs to that person only and it is up to that witch who else can read it.