1) The concept of intertextuality was originally developed by Julia Kristeva in the 1960s and refers to how texts reference and borrow from other texts. 2) Kristeva argued that readers approach new texts with preexisting knowledge and meanings from other texts they have consumed, shaping their interpretations. 3) Key proponents of intertextuality theory include Julia Kristeva, who coined the term, and M.H. Abrams, who defined it as the ways a text echoes or is linked to other texts through citations, allusions, assimilated features, or participation in common literary conventions.