Popular song is a liminal, hybrid form of cultural production. As a manifestation of adaptation studies, it has lacked visibility by comparison with more dominant adaptation practices, especially those for the screen. This book serves to fill this gap. It investigates what songwriters read and write before they start singing, showing that they need either to adapt material from existing sources or write their own lyrics drawn from a wide range of source texts and personal experiences. They are subject to myriad influences, and among these are other song lyrics, poems, novels, plays, films and hybrid cultural forms. This deep-structure intertextuality is embedded in the cultural flux of language, and operates at both conscious and subconscious levels. This book thus explores the complex and multifarious intertextual connections between popular songs of various genres, styles and eras and literary works, including, but by no means limited to, the Bible and Shakespeare. As such, it offers a valuable resource, by exploring the deep intertextual significance of literary source material for the intellectual and emotional diversity that can be found in the popular song form; the inverse reciprocal relationship, while much less common, is also considered in the study.