Choosing Wisely Canada and the Canadian Medical Association Journal (CMAJ) have teamed up to create this excellent digital book. It includes background information on the campaign and why it exists, practice cases which highlight unnecessary or harmful tests & treatments, and guidance on five clinical topics. There are also true or false questions that test your knowledge about which medical interventions are warranted.
This digital book is a really cool way to get familiar with the campaign and might be a fantastic manual for teaching. Have a look: