Cannabis: A Big Sisters’ Guide Mary has metastatic breast cancer and wanted to know if cannabis could help. She asked her sister Anna, who taught chemical safety and knew all about cannabis. They wrote a book to help people who wanted to know more about modern marijuana. Find out if cannabis is right for you with this fun and informative guide. * What is so special about the cannabis plant. * What are THC and CBD * Medical conditions cannabis can help * Learn how to use cannabis safely * How to roll a joint * Anatomy of a bong * How to get a medical marijuana card * Tips for visiting a dispensary