One form of spying, treason, is one of the earliest crimes punished by society, and the only crime defined in the U.S. Constitution. Even though "sub rosa crime" is more costly than traditional property crime and has altered post World War II economic and political history, it has been relatively neglected in the criminological literature. A new typology of spies is proposed and case illustrations are described which attempt to alleviate overconcentration upon ideological spies and include: mercenary, alienated, buccaneer, professional, compromised, deceived, quasi-agent, escapee, and miscellaneous. 60 references, 1 figure. (Author abstract)