The Constitution of Man (or more completely, The Constitution of Man Considered in Relation to External Objects) first published in 1828 is a work by George Combe, who is credited with popularizing the science of Phrenology. Combe argues that the human mind is best understood through Phrenology, and that the relative size of the various regions of the brain defined by Phrenology determines a person's behavior and potential interactions with the external world. In The Constitution of Man, Combe uses Phrenology to create a practical science of morality, proposing that conforming to natural laws leads to happiness based on the Phrenological understanding of human nature. The book was an international bestseller, selling at least 100,000 copies in Britain alone and over 300,000 copies worldwide by 1855, largely due to the publication of the 'people's edition,' making it one of the best-sellers of the nineteenth century. Summary/Content Preface Combe prefaces his work by stating, "no author has hitherto attempted to point out, in a combined and systematic form, the relations between [the laws of nature] and the constitution of Man; which must, nevertheless, be done...The great object of the following Essay is to exhibit these relations, with a view to the improvement of education, and the regulation of individual conduct." He explains his use of Phrenology in the work by saying, "Phrenology appears to me to be the clearest, most complete, and best supported system of Human Nature." Combe aims to use Phrenology to develop a concept of the relationship between human nature and the external world. Chapter I: On Natural Laws In Chapter I, Combe defines the Natural Laws, categorizes them, and identifies principles concerning the Natural Laws. For Combe, "A law...denotes a rule of action; its existence indicates an established and constant mode, or process, according to which phenomena take place." Natural Laws refer to "the rules of action impressed on objects and beings by their natural constitution" Combe presents the relationship between God, Nature, and the Natural Laws: "If, then, the reader keep in view that God is the creator; that Nature, in the general sense, means the world which He has made; and, in a more limited sense, the particular constitution which he has bestowed on any special object...and that a Law of Nature means the established mode in which that constitution acts, and the obligation thereby imposed on intelligent beings to attend to it, he will