Considered a masterpiece of travel literature for nearly a century, The Sea and the Jungle is a wise and witty book of firsts: ostensibly a lighthearted story of a Londoner's first ocean voyage, it is also a carefully crafted journalistic account of the first successful ascent of the Amazon River and its tributary, the Madeira, by an English steamer. First published in 1912, The Sea and the Jungle remains one of the most popular accounts of a traveler's experience in Amazonia. As Peter Matthiessen observed fifty years later, " The Sea and the Jungle is one of the few level-headed works in the literature of this region. . . . accurate and difficult to improve upon."

Henry Major Tomlinson (21 June 1873 – 5 February 1958) was a British writer and journalist. He was known for anti-war and travel writing, novels and short stories, especially of life at sea.