These days, firesetting and arson seem to be on the increase. The detection of arson cases can result only from the thorough investigation of all fires. Currently, firefighters play a vital role in fire investigation. Indeed they are the first arrivals to the fire scene. They will need to be observant for the different indicators at the fire scene. There will be those who will judge if the fire was natural, accidentally or malicious. They will warn in this last case the competence of more suitable people: policemen, forensics, dog handlers… Therefore until the “fire investigators” arrive, the firefighters will be their eyes and ears; what they see and hear will be the key to future success. The “Fire Investigators” will have to be aware of information picked up by firefighters. It is why communication between firefighters and “Fire Investigators” is a basic requirement. The purpose of this book is to enable firefighers, through the substantial nature of the information given in this report, to recognise the first signs of arson and to behave properly at the fire scene to enable a further examination.