James Hilton (novelist) picked "Lost Horizon" as its first title in 1939. For that reason, the novel is frequently called the book that began the "paperback revolution." Hilton is said to have been inspired to write "Lost Horizon", and to invent "Shangri-La" by reading the "National Geographic Magazine" articles of Joseph Rock, an Austrian-American botanist and ethnologist exploring the southwestern Chinese provinces and Tibetan borderlands. Still living in Britain at the time, Hilton was perhaps influenced by the Tibetan travel articles of early travellers in Tibet whose writings were found in the British Library. Christian Zeeman, the Danish father of the mathematician Christopher
Paradise Lost temptation of Adam and Eve by the fallen angel Satan and their expulsion from the Garden of Eden. Milton's purpose, stated in Book I, is to "justify the ways of God to men". In his introduction to the Penguin edition of "Paradise Lost", the Milton scholar John Leonard notes, "John Milton was nearly sixty when he published Paradise Lost in 1667. The biographer John Aubrey (1626–97) tells us that the poem was begun in about 1658 and finished in about 1663. However, parts were almost certainly written earlier, and its roots lie in Milton's earliest youth." Leonard speculates that the