The Muse in Arms is an anthology of British war poetry published in November 1917 during World War I. It consists of 131 poems by 52 contributors, with the poems divided into fourteen thematic sections. The poets were from all three branches of the armed services, land, sea and air, from a range of ranks and from many parts of the UK. Twenty of the poets who contributed to this volume died during the war. The editor was the journalist and author Edward Bolland Osborn (1867–1938), and the book was printed in London by the publishers John Murray. This anthology was one of several collections of war poetry published in the UK during the war. It "achieved large sales", and was reprinted in February 1918. It has been referenced in several analyses of First World War poetry and has been described as "the most celebrated collection of the war years".

Rear Admiral Ronald Arthur Hopwood was a British naval officer and poet. He began his career in 1882 with the Royal Navy as a gunnery officer, completed it in 1919 as a rear admiral, and was acclaimed in 1941 as poet laureate of the Royal Navy by Time. As an author, Admiral Hopwood's first work was his poem The Laws of the Navy, published in 1896 when he was a lieutenant. With its good-natured military advice making it popular within both the Royal and U.S. navies, Time gives it "precedence among Navy men even over Kipling's If" and goes on to quote Hopwood's new poem Secret Orders in its entirety. The last lines of Secret Orders, written in appreciation of the Destroyers for Bases Agreement, harken to the Second World War bond between the two navies.