A 1797 portrait
He wrote Mejnoun and Leila, an oriental story, but his fame was assured by his best known work, Curiosities of Literature, a collection of anecdotes about historical persons and events, unusual books, and the habits of book-collectors. The work was very popular and sold widely in the 19th century, going through many editions -- it was first published in four volumes over several years but then combined into one. It is still in print. His book The Life and Reign of Charles I (1828) resulted in his being awarded the degree of D.C.L. from Oxford University
In 1841 he became blind and, though he underwent an operation, his sight was not restored. He continued writing, however, and with his daughter's assistance he produced Amenities of Literature (1841) and completed the revision of his work on Charles I. He died at age 82, at his home, Bradenham House, in Buckinghamshire on January 19, 1848, less than a year after the death of his wife, Maria Basevi D'Israeli, in the spring of 1847. They had been married for some forty years and had four children: Sarah ("Sa"), Benjamin ("Dizzy"), Raphael ("Ralph"), and Jacobus ("James").
Isaac had changed the spelling of his children's last name to make it less foreign-sounding, and he had them baptized as Christians in 1817, although he himself remained a Jew. This was what allowed his famous son Benjamin to enter Parliament, years before Jews could sit in that legislature, and Benjamin was a staunch supporter of Baron Rothschild when he was elected to the House of Commons but not allowed to serve there. (That restriction was eventually lifted, and Rothschild became the first Jewish member of the House.)