The infrastructures addressed in this paper represent a framework of inter-dependent networks and systems comprising industries, institutions, functions, and distribution capabilities. They provide a continual flow of goods and services essential to the economic well-being and security of the United States, as well as to its defense. On the National and commercial side, the infrastructure is defined by nine areas or sectors. These are: Banking and Finance; Transportation; Electric and Gas (Power); Information and Communications (Telecommunications); Law Enforcement; Government Services; Fire; Emergency Health Services; and the Water Supply. On the Defense side they are: Financial Services; Transportation; Public Works; Defense Information Infrastructure and Command, Control, and Communications; Intelligence, Surveillance and Reconnaissance; Health Affairs; Personnel; Logistics; and Space. And while the commercial side doesn't necessarily depend on the Defense side for its survival, with the exception of Public Works, the same cannot be said for the Department of Defense. The reader should gain a sense that, in general, critical infrastructure protection is not insurmountable. In fact, protecting the infrastructure is something we do daily, especially in the Department of Defense for those infrastructures that we own and operate. And the reader should take away the knowledge that there is considerable thought and debate going into the subject.