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 (though mostly officers) 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".
The anthology's title page describes the book as "A collection of war poems, for the most part written in the field of action, by seamen, soldiers, and flying men who are serving, or have served, in the Great War". The dedication is to the journalist and Times Literary Supplement editor Bruce Lyttelton Richmond (1871–1964).
The first edition of the book contains 38 pages of prefatory material including publication details, the dedication, an introduction by the editor, acknowledgments (several of the poems had been previously published), a list of 46 authors, and a list of contents. This is followed by 131 poems over 295 pages. Eight of the 131 poems are by civilian or anonymous authors, some referenced by name or pseudonym and others only by their initials, bringing the total number of contributors to 52.
Osborn's introduction discusses several aspects of the collection and includes a quote from Pericles when considering the cost of the war against the poetry produced:
But the youth we have lost in these dread years has not perished in vain; if "the spring has gone out of the year," as Pericles lamented, yet we are immeasurably the richer for the spirituality they have bequeathed to us, of which the poems in this book are an enduring expression.
The book is divided into fourteen thematic sections:
At the time of the anthology's publication in November 1917, the death during the war of sixteen of the forty-six authors was marked in the list of authors with an asterisk, and are so-marked in the following list as well. The deaths during the war of four other authors who were killed or died following publication of the book, or whose deaths had occurred earlier but not been recorded by Osborn, are marked with a double asterisk. The military rank and unit given in the list of authors is also included in the list below.