London during a Parliamentary hearing. In 1998, Microsoft co-founder Bill Gates was pied in Belgium. There are varying types of executive protection. They can generally be divided into the following categories: High-threat protection for dignitaries traveling internationally Corporate executive protection for high net-worth corporate officers Celebrity close protection The defining characteristics among these categories are first, the amount of resources available for the task, and second the types of environments that they operate in on a routine basis. See also Security detail References Further reading Aitch, Richard (2012). "Close Protection - A Closer Observation of the Protection Equation". London, UK. June, Dale (1998). Introduction to Executive Protection. Boca Raton, Fla.: CRC Press. 978-0849381287. Oatman, Robert (2006). Executive Protection: New Solutions for a New Era. Baltimore, Md.: Noble House. 978-1561679423. Braunig, Martha J. (1993). The Executive Protection Bible. Aspen, Colo.: ESI Education Development Corp. . De Becker, Gavin (2002). Fear Less: Real Truth About Risk, Safety, and Security in a Time of Terrorism. Boston: Little, Brown. . De Becker, Gavin (1997). The Gift of Fear: Survival Signals That Protect Us from Violence. Boston: Little, Brown. . De Becker, Gavin, Thomas A. Taylor, and Jeff Marquart (2008). Just 2 Seconds: Using Time and Space to Defeat Assassins: with a Compendium of Attacks against at-Risk Persons. Studio City, Calif.: Gavin de Becker Center for the Study and Reduction of Violence. . [www.just2seconds.org] De Becker, Gavin (1999). Protecting the Gift: Keeping Children and Teenagers Safe (and Parents Sane). New York: Dial Press. . Karlin, Susan (November 8, 2007). "Covering Your Assets". Condé Nast Portfolio. Karlin, Susan (November 8, 2007). "How to Choose an Executive Protection Firm". Condé Nast Portfolio. Karlin, Susan (December 9, 2007). "The Secret Weapon of the Stars". ISRAEL21c. Kobetz, Richard W., ed. (1991). Providing Executive Protection. Executive Protection Institute. , . Kobetz, Richard W., ed. (1994). Providing Executive Protection, Volume II. : Executive Protection Institute. . Oatman, Robert L. (1997). The Art of Executive Protection. Baltimore, Md.: Noble House. . Colliver,"Rick"R.E.(2011)."Principal Protection; Lessons learned". Dublin, Oh.: Terrapin Group Publications. Patrick Van Horne and Jason A. Riley (2014). "Left of Bang How the Marine Corps' Combat Hunter Program Can Save Your Life". New York, NY: Black Irish Entertainment LLC. . Security