Fire has posed a preeminent threat to human society since man first began constructing buildings and grouping them into towns and cities. To counter this threat, gypsum plaster’s unique fire resistant properties have been used for centuries to protect buildings from fire. After the Great Fire of London in 1666, France’s Louis XIV feared that his capital city could suffer the same fate. He issued a royal decree in 1667 ordering that all wooden buildings were to be protected with gypsum plaster. Thus, one of the earliest fire codes led to this remarkable material becoming known as plaster of Paris. The science of fire safety engineering has advanced greatly over the years to give us an in-depth understanding of the critical stages of fire initiation, growth, containment and suppression. Such knowledge has enabled today’s building codes and fire protection engineers to provide fire safe structures for our homes and cities. This section presents the fundamentals of building fire protection.