Michael Henry Gill purchased the publishing and bookselling business of James McGlashan in 1856; formerly Gill had been printer for the University of Dublin. The two formed McGlashan and Gill, which became in 1875 M.H. Gill and Son. The bookshop the company owned was located in O'Connell Street in Dublin, Ireland for 123 years, only closing in 1979. In 1968 Michael Gill founded Gill and Macmillan, which continues to function as Gill Books.

Gill and Son began publishing the Catholic Bulletin and Book Review in 1911 (initial title Catholic Bulletin: A Monthly Review of Catholic Literature). Patrick Keohane, managing editor at Gill and Son, founded the Bulletin and sometimes edited it himself. A monthly magazine, its original aim was to produce and promote wholesome literature for the family and the Irish language, and its contributors included several priests and bishops, as well as members of the Gaelic League.

The Bulletin provided precise details about the individuals involved during the Easter Rising and otherwise supported the efforts for Irish independence during the 1910s and 1920s, mostly through the efforts of its first editor, John Joseph O'Kelly. The magazine also typically included in its issues an editorial, fiction, poetry, a children's corner, a section for mothers and daughters, historical selections, and a "matters of the moment" section. O'Kelly was editor of the Bulletin until 1922 when he left Ireland; the final issue of the publication was produced in December 1939, the same month that Patrick Keohane died.

John Joseph O'Kelly (Seán Ua Ceallaigh) was born in 1872 on Valentia Island, County Kerry, Ireland to Patrick and Ellen (O'Sullivan) Kelly. He learned Irish from his father, from storytellers on the island, and from reading the Irish columns in newspapers. He went on to teach the language when he moved to Dublin in 1897.

Besides teaching, O'Kelly earned income from journalism, writing for the Irish People and Freeman's Journal. O'Kelly joined the Society for the Preservation of the Irish Language and the commercial branch of the Gaelic League, serving a brief appointment as its assistant secretary. He was also a founding member of the Sinn Féin party in 1905. In 1904 he married Nora O'Sullivan of Lisbawn, County Kerry.

O'Kelly did not participate in the Easter Rising of 1916 himself but supported those individuals involved and the republican ideals of the Rising through his editorial responsibilities with the Catholic Bulletin. He also was appointed treasurer of the Irish National Aid and Volunteers' Dependents Fund, vice-president of the Gaelic League in 1916, and became a council member of the Irish National League in 1917. O'Kelly was elected the Sinn Féin candidate for Louth in the general election of 1918 and served as deputy speaker of the first Dáil Éireann, resigning that position at the second dáil in August 1921.

O'Kelly was opposed to the terms of the peace treaty negotiations occurring between British Prime Minister David Lloyd George and Eamon de Valera of 1921. In 1922 he went to America to gain Irish-American support against the treaty; in 1923, he went to Australia with Father O'Flanagan on the same purpose. Their Australian tour had them arrested twice, and they were finally deported to America in July 1923.

O'Kelly continued to espouse republican principles (the independence of Ireland from English rule) the rest of his life, serving as president of Sinn Féin from 1926-1931 and writing a wide range of books, pamphlets, poetry, and articles in both Irish and English and under the Irish version of his name Seán Ua (Ó) Ceallaigh, as well as pen names that included Sceilg, Fear Siúil, S Ua C, and Mogh Ruith.

John Joseph O'Kelly died 26 March 1957.