This thesis investigates the career(s) of Matthew Davenport Mill, 1792-1872. Chapter I begins with an evaluation of his social origins and concludes with a character sketch and notes on Hill as others have seen him. Chapter II comprises a detailed examination of the 'progresive, Hazelwood School, Birmingham, owned and run by the Hill family from 1803 to 1833, with special reference to Matthew's contribution to it. The educational significance of the school is considered as also is the influence of the Hazelwood experience on Hill's subsequent development. In 1819 Hill was called to the Bar but, still interested in the subject of education, he joined the Committee of Henry Brougham's Society for the Diffusion of Useful Knowledge in 1826. His activity within this organization, over a twenty year period, is examined in chapter III. Whilst a member of the S. D. U. K. Mill was elected M.P. for the borough of Kingston-upon- Hull. His Parliamentary performance, between 1832 and 1834, and his two election contests are analysed in chapter IV. Chapter V deals with his appointment as Recorder of his native Birmingham in 1839- It concentrates on his relations with the municipal authorities in the period to his resignation in 1867. As Recorder Hill developed, expounded, and attempted to implement the penal philosophy for which he Is now chiefly remembered. The next four chapters investigate the nature of this philosophy and also Hill's r8les in the juvenile reformatory movement and the ticket-of-leave controversy which surrounded the run-down of transportation and the establishment of the new punishment of penal servitude. In conclusion this study tests the hypothesis that during his career Hill moved away from liberalism to a standpoint of repressiveness. To this end his political, professional, and social ideas, over a period of some fifty years, are surveyed. Also, an attempt is made to place Hill's career in historical perspective by evaluating his significance as a reformer.