A 'kind of agent' is a broad term that can refer to many different types of people who work in various fields. SECRET agents are those who work in espionage and intelligence gathering, often in a clandestine manner. Chemical agents are those who work with chemicals, such as chemists or chemical engineers. Causal agents are those who investigate the causes of events, such as insurance investigators. FBI agents are those who work for the Federal Bureau of Investigation. IRS agents are those who work for the Internal Revenue Service. PRESS agents are those who work in public relations and media relations. TRAVEL agents are those who help people plan and book their TRAVEL arrangements. UNDERCOVER agents are those who work in SECRET, often infiltrating organizations to gather information.