The Royal College of Defence Studies (RCDS) is an institute of higher education that instructs the most promising senior officers of the British Armed Forces, His Majesty's Diplomatic Service and Civil Service in national defence and international security matters at the highest level, to prepare them for the top posts in their respective services. It forms part of the Defence Academy of the United Kingdom, and is its most senior and prestigious component. In addition, there are many overseas attendees from countries who are close allies of the United Kingdom.