Pennell was born in Philadelphia where he was trained before making the European trip to learn and draw. In 1884 he settled in the UK which became his working base. He wrote extensively, not least about his master J.M.Whistler whose 2 volume biography (1906) he undertook together with his wife, Elizabeth. When attracted to unusual subjects he was at his inventive best. But he was too prolific, reaching too often for the genteel and picturesque subject with a shallow vignetted approach. He is at his best in the illustrations to Walter Besant's East End of London, and in the War Work in England. He doesn't really thrive on modernity but keeps one cautious foot in the print making conventions.