Howard Pyle (1853-1911), was an American artist and author, who changed the way the world looked at illustration and the way illustration looked to the world. Pyle wrote many of the books and stories he illustrated, and though he will always be remembered first for his art, many of his books are considered classics.
These include: The Merry Adventures of Robin Hood, Pepper & Salt, The Wonder Clock, Otto of the Silver Hand, Men of Iron, The Garden Behind the Moon, and the four volume Arthurian legends comprised of The Story of King Arthur and His Knights, The Story of the Champions of the Round Table, The Story of Lancelot and His Companions, and The Story of the Grail and the Passing of Arthur.
Most of these were illustrated with his distinctive pen & ink style that hearkened back to the wood-engraved images that were common during his childhood and early years of his career. He wasn't restricted to this more-formal style, but seemed to gravitate towards it in pen illustrations for his own work.