This book is a detailed critique of the Hamiltonian theory of limitation, which claims that human knowledge is inherently limited. Howison challenges this notion by examining the works of Rev. Henry L. Mansel and Herbert Spencer, who both adopt and extend Hamilton's ideas. Howison argues that their theories are flawed and that human knowledge is not as restricted as they claim. The book is a philosophical exploration of the nature of knowledge, the limits of understanding, and the potential of human thought.