This foundational chapter equips readers for theological inquiry by tracing the term “theology” from its Greek philosophical origins to its systematic development in Christian thought. It establishes the crucial philosophical divergence between idealism (reality as mind-dependent) and realism (reality as objective) as a key framework for understanding theological approaches. The chapter then introduces the pivotal work of Don Tommaso Demaria, who argues that the Industrial Revolution caused a fundamental ontological shift from a “static-sacral” society, animated by religion, to a “dynamic-secular” Historical Reality. This new, constructed reality is no longer governed by religion but by ideology. Consequently, Demaria posits the need for a new “realistic-dynamic metaphysics” to adequately understand and act within this modern, ever-changing world, setting the stage for the book’s subsequent analysis of contemporary challenges.