Among his many publications are a Handbook to the Popular, Poetical and Dramatic Literature of Great Britain: From the Invention of Printing to the Restoration. J.R. Smith. 1867., supplemented in 1876, 1882, 1887 and 1889, a General Index by J. G. Gray appearing in 1893. Hazlitt published further contributions to the subject in Bibliographical Collections and Notes on Early English Literature, Made During the Years 1893–1903 (1903), and a Manual for the Collector and Amateur of Old English Plays ... (1892). He was also the chief editor of an edition of Warton's History of English Poetry (1871) and compiled the Catalogue of the Huth Library (1880).
He also published Collections and Notes, 1867-1876 (London: Reeves & Turner, 1876, containing detailed bibliographical entries on many early English printed books) followed by Bibliographical Collections and Notes on Early English Literature 1474-1700: Second Supplement. Quaritch. 1882.. His autobiography is The Confessions of a Collector. 1897..
In 1875, he published an edition of the works of Thomas Randolph.
He published The History of the Venetian Republic: Her Rise, Her Greatness, and Her Civilization. Smith. 1860. and Old Cookery Books and Ancient Cuisine. 1886..
Of great use, interest and delight to gardeners and collectors of herbals, etc. is his Gleanings in Old Garden Literature, published by Elliot Stock, London, 1887, in The Book-Lover's Library. This book includes, in its final chapter, a Bibliography of Gardening Literature, 1603 - 1800, and of Herbals and Bee Culture.