Explore the theoretical landscape of quantum gravity through this comprehensive lecture that examines the swampland program, a framework distinguishing consistent quantum gravity theories from inconsistent ones. Delve into the fundamental principles that govern which effective field theories can be consistently coupled to quantum gravity, learning about swampland conjectures and their implications for string theory and cosmology. Discover how these theoretical constraints shape our understanding of the universe's fundamental structure, from the behavior of scalar fields to the nature of de Sitter space, while examining specific examples and mathematical formulations that illustrate why certain theories belong in the "swampland" of inconsistent quantum gravity models.