"Here it is up front: intelligence is, with thanks to Constantine FitzGibbon, knowledge of the enemy. No sooner is it written than the readers' rejoinders flash in the mind, form on the lips, strike the air: No, it's wrong, inadequate, misleading, or impolitic; or, So, what else is new? Rest assured, dear rejoinder-ers, that these objections will be handled long before the last page is reached... so many of those intelligencers who have tried to define intelligence have grievously botched the job. Finally, unless intelligence is properly understood, the country's intelligence agencies, faced with changing targets and priorities, may lose sight of their proper task."

"The debate within Intelligence studies over its central conceptual term is by no means a discipline-specific problem. International security experts have debated the term “terrorism” ad nauseam, while biologistshave been at war over the term “species” for over two centuries. In contrast to these parallel debates over the respective essences of “terrorism” or “species”, scholars of intelligence add that intelligence is under-theorized. In short, they posit the following: if we think harder we could get a better, more functional, definition of intelligence."

"Formulating a brief definition of so broad a term as intelligence is like making a microscopic portrait of a continent, and the product of this effort is likely to have less value than the process of arriving at it, the reexamination of our own thinking as we seek to pinpoint the essentials of the concept."

""Indeed, even today, we have no accepted definition of intelligence. The term is defined anew by each author who addresses it, and these definitions rarely refer to one another or build off what has been written before. Without a clear idea of what intelligence is, how can we develop a theory to explain how it works?"

"For producers of intelligence, however, the equation "intelligence = information" is too vague to provide real guidance in their work. To professionals in the field, mere data is not intelligence; thus these definitions are incomplete. Think of how many names are in the telephone book, and how few of those names anyone ever seeks. It is what people do with data and information that gives them the special quality that we casually call "intelligence.""