The core principles of structural firefighting are fire behavior, building construction, strategy, tactics, safety and training. Each core principle is examined with relevant on-the-job stories to bring lessons home. Fire departments must constantly train their firefighters and officers in these core principles if they want them to be safe and effective at structure fires. Training is the foundation of all the other core principles, and must be realistic, scenario-based, and hands-on. Never stop learning during your time as a structural firefighter. If you come to a point where you mistakenly believe that you know everything there is to know about fires in and around buildings-watch out-because you have just fallen into the complacency trap.