The CMQ/OE Mind Map Book is created by The Mind Map Series Group. It is about 32 pages of mind maps, which covers the BOK of the ASQ CMQ/OE.
It is mainly a note-taking system to help you with recalling specific information and serves as a memory palace, which can be helpful with memorizing abstract information.
One suggested way of using this book is after reviewing the relevant material, in preparation for the exam. It can help you link all the subjects together and build a mental image for them.