The book is a collection essays. In these essay matters like mankind and politics and discussed. The ensuing essay concerning the growth of the city of London was entitled "Another Essay", intimating that some other essay had preceded it, which was not to be found. I having been much importuned for that precedent essay, have found that the same was about the growth, increase, and multiplication of mankind, which subject should in order of nature precede that of the growth of the city of London, but am not able to procure the essay itself, only I have obtained from a gentleman, who sometimes corresponded with Sir W. Petty, an extract of a letter from Sir William to him, which I verily believe containeth the scope thereof; wherefore, I must desire the reader to be content therewith, till more can be had. The extract of a letter concerning the scope of an essay intended to precede another essay concerning the growth of the City of London, &c. An Essay in Political Arithmetic, concerning the value and increase of People and Colonies. The scope of this essay is concerning people and colonies, and to make way for "Another Essay" concerning the growth of the city of London. I desire in this first essay to give the world some light concerning the numbers of people in England, with Wales, and in Ireland; as also of the number of houses and families wherein they live, and of acres they occupy.