Letter from Andrew Philip Magill to William O'Brien acknowledging of receipt of O'Brien's letter concerning the control of shipping.Andrew Philip Magill (1871-1941) had a varied career in the Irish civil service; he moved to the Ministry of Home Affairs in Northern Ireland before resigning prematurely in 1925. As private secretary to Augustine Birrell, the Chief Secretary whose resignation was prompted by the 1916 Rising, Magill was well placed to observe the often bizarre workings of the pre-revolutionary Irish administration. His subsequent postings in Dublin and Belfast likewise made him an invaluable witness of conflicts associated with revolution and partition.William O'Brien (1881-1968) was a politican and trade unionist. A close friend and associate of James Connolly, O'Brien helped establish the Irish Transport and General Workers' Union in 1909, and was instrumental in the Dublin Lock-out strike in 1913. A member of the Irish Neutrality League, and Anti-Conscription Committee, during the World War I, O'Brien was interned on several occasions by the Dublin Castle government. From 1913 until 1918 O'Brien served as secreatry of the Dublin Trades Council.