This book of documents aims to analyze the British Foreign Office's policy regarding the Macedonian Question in the interwar period and its reflection on the diplomatic relations between the United Kingdom and Bulgaria as well as with the other Balkan countries involved. The selected documents review the policy of the British Foreign Office towards the Macedonian Question. The British Foreign Office's policy, formulated at the Paris Peace Conference, had always been aiming at weakening the issue. Gradually, the British diplomatic efforts focused on prohibiting the Internal Macedonian Revolutionary Organization (IMRO) and on its complete disbanding. The end of IMRO in 1934, however, did not bring the desired end to the Macedonian Question. WWII revived the unresolved national questions once again. The selected documents have not been published yet and are of great use and interest for many scholars and students. The presented documents are not only part of the diplomatic correspondence between Sofia and London but also part of the correspondence between the British Foreign Office and its representatives, mainly Athens and Belgrade.