Latterly, I acknowledge, much of my seriousness has gone off…but I still retain at bottom a conviction of the truth, and a certainty of the usefulness of religion." In the later letters it is often possible to see Lamb forming and developing the ideas that he later presented in fully matured form in the "Essays of Elia" and other magazine pieces, and in this way they proved to be essential to his career as a published writer. The humour and (as he often said) "nonsense" of his letters is sometimes seen as a disguise for mental instability and deep anguish. The essayist Augustine Birrell wrote that "He took refuge in trivialities seriously, and played the fool in order to remain sane." The letters have a great deal to say about Lamb's incessant reading, often among 17th century writers, and it has been argued that his love of Robert Burton, Thomas Browne and the Jacobean tragedies may show an underlying depression and despair which answered to theirs. Lamb's words on Burton have frequently been taken as applying to himself: "Burton was a man often assailed by deepest melancholy, and at other times much given to laughing and jesting, as is the way with melancholy men." Thackeray was so impressed by the beauty of Lamb's character as revealed in his letters that he once pressed one of them to his forehead and exclaimed "Saint Charles!" It was the opinion of Thomas Noon Talfourd, who knew Lamb well, that there was scarcely one of his letters "which has not some tinge of that quaint sweetness, some hint of that peculiar union of kindness and whim, which distinguishes him from all other poets and humorists." Lamb's reputation as a writer may have fallen since the 19th and early 20th centuries, at any rate among academic critics, but he has never been short of readers who agree with the essayist E. V. Lucas as to "the value and importance of these letters, their good sense, their wit, their humanity, their fun, their timeliness and timelessness". As early as February 1835 a decision was made to prepare a collection of Lamb's letters. Thomas Noon Talfourd was chosen as the editor, and his "Letters of Charles Lamb" appeared in 1837. 180 of Lamb's letters appeared in this collection, according to Edwin Marrs's count, though Talfourd's contents page suggests a different number because of his (and several later editors') practice of separating and recombining passages to form, in effect, letters that never were.