The book is about the inverse gravity cosmology hypothesis which is based on three of the author's published papers which past peer review. Hence, the book presents the inverse gravity concept, its mathematical structure, and its incorporation to established and proven aspects of physics. New developments and mathematics of the theoretical concept are expressed. Moreover, the book cites mistakes/deficiencies and omissions in previous publications. Lastly, the book's introduction includes information about the author's background that inspired the inception of the theoretical concept.