Samuel Johnson was an 18th-century English writer, lexicographer, and critic. He is best known for his influential work "A Dictionary of the English Language," which was published in 1755 and was considered a landmark in the history of English language and lexicography. Johnson was also a prolific essayist and literary critic, and he contributed significantly to English literature through his essays, poetry, and biographies. He was a central figure in the London literary scene and was known for his wit, intelligence, and strong personality. Johnson's impact on English literature and language continues to be felt to this day.