These notes are intended to accompany the course Introduction to Variations of Hodge Structure (VHS) at the 2010 ICTP Summer School on Hodge Theory. The modern theory of variations of Hodge structure (although some authors have referred to this period as the pre-history) begins with the work of Griffiths [23, 24, 25] and continues with that of Deligne [17, 18, 19], and Schmid [41]. The basic ob...