St. John Ambulance has been Canada's premier supplier of first aid and CPR training for over 100 years, and this is the guide they use to teach first aid. Now, for the first time, it is available to the general public. St. John's Ambulance's first aid guidelines are based on years or research and are endorsed by the medical community. The St. John Ambulance Guide to First Aid and CPR can make the difference between life and death.