Short answers, pulled from the story.
Smith, Elder & Co. was founded by George Smith, born in 1789, and Alexander Elder, born in 1790. After George Smith's death in 1846, George Murray Smith, born in 1824, continued the firm and guided it through its most productive decades.
Smith, Elder & Co.'s first major success was the publication of Jane Eyre in 1847. The novel was submitted under the pseudonym Currer Bell, but the author was Charlotte Brontë.
Smith, Elder & Co. is known to have been publishing as early as 1826. Works appeared under the firm's name as late as 1936, well after John Murray acquired the company in the early 1900s.
Smith, Elder & Co. published Robert Browning, George Eliot, Elizabeth Gaskell, Thomas Hardy, Alfred Tennyson, Algernon Charles Swinburne, and George Gissing, among others. John Ruskin, William Makepeace Thackeray, Richard Jefferies, George MacDonald, and Charles Reade also published with the firm.
Smith, Elder & Co. produced the first edition of the Dictionary of National Biography, a reference work documenting the notable figures of British history.
John Murray purchased Smith, Elder & Co. in the early 1900s. The firm's archive became part of the John Murray Archive, which is now held at the National Library of Scotland in Edinburgh.