Who is Thomas Carlyle?

I presently am mreading The Bostonians, by Henry James, published 1886 to be a satire of the feminist movement in Boston. The main characters are Olive Chancellor, a young, wealthy spinster who detests men and holds a suspicious view on the intentions of everyone male; Verena Tarrant, a blossoming youth with a gift for inspired soliloquy, whom Olive convinces to take up her own vocation; and Basil Rancom, a chivalrous, unscussessful lawyer cousin whom Olive invites to Boston from his squalid post-Civil War-era farm in Mississippi.

Now nearly half-way through the story, I read that Olive's sister, the widowed Mrs. Adeline Luna (winering in New York with her young son Newton) practically demands in a note to Basil that (after a six-month hiatus) he come to visit her (the narrator reveals that she should like to marry him) from his newly-squalid tenemet rooms on the East Side. Still unsuccessful as a lawyer, Basil tried editorializing, equally unsuccessfully. (The narrator says that, contrary to the beliefs of a contrary editor, Basil is ahead of his time.) He contemplates politics because he likes to think on the betterment of society. He lenjoys reading de Tocqueville and Thomas Carlyle.

Which set me wondering: Who is Thomas Carlyle? I found his complete Works, and save them here for future reference.