Learning from Experience
Spying is said to be the second oldest profession. (For those who need to ask, the oldest is prostitution.) Like the oldest profession, the basics of espionage really haven't changed much over the past two thousand years. But there are a number of newer developments in the kinds of people involved, what they are after, how they accomplish the dirty deed, and how they are caught.
Experience is the best teacher, so the past
cases summarized here have been selected from among many others because they
describe or illustrate important points. Some timeless truths that need to
be learned may be best illustrated by an older case. Due to security, legal,
privacy, and practical bureaucratic considerations, it may be many years
after an arrest and conviction before information is declassified and
becomes available for broad dissemination.