The manuscript is titled, on 2v, "Diarie of the Transactions for the expedition against the French in the yeare 1745—from April the 6th till January 1746 by me. / John Curtice / Captn 8th Co Mass R. / of Worcester New Engld". It is Curtice's first-hand account of the siege and occupation of the fortified seaport of Louisbourg, on Cape Breton Island in Nova Scotia. The text of the diary is written in the margins of a printed book: Francis Gentleman's The History of the Robinhood Society, published in London in 1764. The content of the book is of no relevance to the content of the diary. Thus, this copy of the diary necessarily postdates the events described by at least nineteen years. Nothing in the existing volume suggests why, when, or by whom the copy was made. Still, there is no reason to doubt its status as a transcription of a lost original, kept by Curtice during the Louisbourg siege. Relevant to this is the fact that a second copy diary of Curtice's exists, recording his experiences in the Montreal campaign of 1760, during the French and Indian War. This, too, is copied in a printed book, published in 1776; its formatting is like that of the Louisbourg diary in every respect, and it is written in the same scrupulous eighteenth century hand. It seems probable that the two volumes were copied on the same occasion. If this is so, the Louisbourg manuscript would almost certainly date from the last quarter of the eighteenth century. An attribution to Curtice himself seems likely, though this cannot be proved.

The diary is a single volume (17 cm.) of 131 leaves, with 96 pages of entries in a single hand. There are also four paper slips tipped into the gutters of the volume, bearing additional journal text written in the same hand; these describe events for 18 May, 6 June (?), 9 June, and 21 and 22 December 1745. Why these slips were added, or whether they are survivals of the original manuscript, is not clear. Entries uniformly begin in the lower left corner of the rectos of the book's leaves, and run perpendicular to the printed text through the inner, tail, and outer margins, without crossing the text block. In addition to the diary entries, the volume includes a roster of the men under Curtice's command in the 8th Massachusetts Company (1v), as well as a list of the soldiers in Col. Samuel Willard's 4th Massachusetts Regiment who died during the occupation (130v).

With the advent of war between France and Great Britain, the commander at Louisbourg attacked the fishing stations and boats of Nova Scotia, and unleashed his privateers to seize New English ships. In the winter of 1744-1745, Governor William Shirley of Massachusetts proposed an expedition to take Louisbourg. The plan was approved by the Massachusetts General Court and received support from other colonies and from the British, in the form of a naval squadron commanded by Commodore Peter Warren. The expedition embarked on 24 March 1744/5, when roughly 4000 colonial militia under Col. William Pepperrell sailed from Boston to Canso, in Nova Scotia. Curtice's diary entries begin on 6 April 1745, when he and the men of his command were at Canso, and continue through the siege, capture, and occupation of Louisbourg, until 2 February 1746. Entries appear on a near daily basis, except for a significant gap between 6 September and 14 November 1745 when Curtice was "taken sick." Entry length and content vary considerably during and after the siege. Before Louisbourg's surrender on 16 June, entries range from as few as 15 to as many as 125 words and are more or less confined to military operations: (1 May) "Last night I went to the top of the hill where we fired 15 shots at the French & they fired from the city battery at us — last night our watch killed several French & took some Prisoners. They burned several of their houses." Following the surrender, entries are briefer and more varied in content: typical topics include the weather, the illnesses and deaths of colonial soldiers, and difficulties in preserving order among the men. Many in Willard's regiment had volunteered expressly to capture Louisbourg, for the attendant plunder. Following the surrender they believed their duty to be done, yet they were kept at the fort to maintain a British presence while the greater war continued. Disciplinary measures were harsh: "A soldier was whipped 39 lashes for robbing a dead corpse & leaving ye body unburied" (10 August); "A man whipt 5 lashes for prophane swearing & etc. and drawing his sword & threatning a man." (14 August); "Another man whipt 21 lashes at the wipping post on the parade for striking his superior officer." (15 August).