The full title of the first edition of Malthus' essay was "An Essay on the Principle of Population, as it affects the Future Improvement of Society with remarks on the Speculations of Mr. Godwin, M. Condorcet, and Other Writers." The speculations and other writers are explained below.
William Godwin had published his utopian work Enquiry concerning Political Justice in 1793, with later editions in 1796 and 1798. Also, Of Avarice and Profusion (1797). Malthus' remarks on Godwin's work spans chapters 10 through 15 (inclusive) out of nineteen. Godwin responded with Of Population (1820).
The Marquis de Condorcet had published his utopian vision of social progress and the perfectibility of man Esquisse d'un Tableau Historique des Progres de l'Espirit Humain (The Future Progress of the Human Mind) in 1794. Malthus' remarks on Condorcet's work spans chapters 8 and 9.
Malthus' essay was in response to these utopian visions, as he argued:
"This natural inequality of the two powers, of population, and of production of the earth, and that great law of our nature which must constantly keep their effects equal, form the great difficulty that appears to me insurmountable in the way to the perfectibility of society."
The "Other writers" included Robert Wallace, Adam Smith, Richard Price, and David Hume.
Malthus himself claimed:
"The only authors from whose writings I had deduced the principle, which formed the main argument of the Essay, were Hume, Wallace, Adam Smith, and Dr. Price ..."
Chapters 1 and 2 outline Malthus' Principle of Population, and the unequal nature of food supply to population growth. The exponential nature of population growth is today known as the Malthusian growth model. This aspect of Malthus' Principle of Population, together with his assertion that food supply was subject to a linear growth model, would remain unchanged in future editions of his essay. Note that Malthus actually used the terms geometric and arithmetic, respectively.
Chapter 3 examines the overrun of the Roman empire by barbarians, due to population pressure. War as a check on population is examined.
Chapter 4 examines the current state of populousness of civilized nations (particularly Europe). Malthus criticises David Hume for a "probable error" in his "criteria that he proposes as assisting in an estimate of population."
Chapter 5 examines The Poor Laws of Pitt the Younger .
Chapter 6 examines the rapid growth of new colonies such as the former Thirteen Colonies of the United States of America.
Chapter 7 examines checks on population such as pestilence and famine.
Chapter 8 also examines a "probable error" by Wallace "that the difficulty arising from population is at a great distance."
Chapters 16 and 17 examine the causes of the wealth of states, including criticisms of Adam Smith and Richard Price. English wealth is compared with Chinese poverty.
Chapters 18 and 19 set out a theodicy to explain the problem of evil in terms of natural theology. This views the world as a "a mighty process for awakening matter" in which the Supreme Being acting "according to general laws" created "wants of the body" as "necessary to create exertion" which forms "the reasoning faculty". In this way, the principle of population would "tend rather to promote, than impede the general purpose of Providence."
The 1st edition influenced writers of natural theology such as William Paley and Thomas Chalmers.
[edit]2nd to 6th editions

Following both widespread praise and criticism of his essay, Malthus revised his arguments and recognized other influences:
"In the course of this enquiry I found that much more had been done than I had been aware of, when I first published the Essay. The poverty and misery arising from a too rapid increase of population had been distinctly seen, and the most violent remedies proposed, so long ago as the times of Plato and Aristotle. And of late years the subject has been treated in such a manner by some of the French Economists; occasionally by Montesquieu, and, among our own writers, by Dr. Franklin, Sir James Stewart, Mr. Arthur Young, and Mr. Townsend, as to create a natural surprise that it had not excited more of the public attention."
The 2nd edition, published in 1803 (with Malthus now clearly identified as the author), was entitled "An Essay on the Principle of Population; or, a View of its Past and Present Effects on Human Happiness; with an enquiry into our Prospects respecting the Future Removal or Mitigation of the Evils which it occasions."
Malthus advised that the 2nd edition "may be considered as a new work", and essentially the subsequent editions were all minor revisions of the 2nd edition. These were published in 1806, 1807, 1817, and 1826.
By far the biggest change was in how the 2nd to 6th editions of the essay were structured, and the most copious and detailed evidence that Malthus presented, more than any previous such book on population. Essentially, for the first time, Malthus examined his own Principle of Population on a region by region basis of world population. The essay was organized in four books:
Book I - Of the Checks to Population in the Less Civilized Parts of the World and in Past Times.
Book II - Of the Checks To Population in the Different States of Modern Europe.
Book III - Of the different Systems or Expedients which have been proposed or have prevailed in Society, as They affect the Evils arising from the Principle of Population.
Book IV - Of our future Prospects respecting the Removal or Mitigation of the Evils arising from the Principle of Population.
Due in part to the highly influential nature of Malthus' work (see main article Thomas Malthus), this approach is regarded as pivotal in establishing the field of demography.
The following controversial quote appears in the second edition:
"A man who is born into a world already possessed, if he cannot get subsistence from his parents on whom he has a just demand, and if the society do not want his labour, has no claim of right to the smallest portion of food, and, in fact, has no business to be where he is. At nature's mighty feast there is no vacant cover for him. She tells him to be gone, and will quickly execute her own orders, if he does not work upon the compassion of some of her guests. If these guests get up and make room for him, other intruders immediately appear demanding the same favour. The report of a provision for all that come, fills the hall with numerous claimants. The order and harmony of the feast is disturbed, the plenty that before reigned is changed into scarcity; and the happiness of the guests is destroyed by the spectacle of misery and dependence in every part of the hall, and by the clamorous importunity of those, who are justly enraged at not finding the provision which they had been taught to expect. The guests learn too late their error, in counter-acting those strict orders to all intruders, issued by the great mistress of the feast, who, wishing that all guests should have plenty, and knowing she could not provide for unlimited numbers, humanely refused to admit fresh comers when her table was already full."
Ecologist Professor Garrett Hardin claims that the preceding passage inspired hostile reactions from many critics. The offending passage of Malthus' essay appeared in the 2nd edition only, as Malthus felt obliged to remove it.[3]
From the 2nd edition onwards - in Book IV - Malthus advocated moral restraint as an additional, and voluntary, check on population. This included such measures as sexual abstinence and late marriage.
As noted by Professor Robert M. Young, Malthus dropped his chapters on natural theology from the 2nd edition onwards. Also, the essay became less of a personal response to William Godwin and Marquis de Condorcet.
[edit]A summary view

A Summary View on the Principle of Population was published in 1830. The author was identified as Rev. T.R. Malthus, A.M., F.R.S. Malthus wrote A Summary View for those who did not have the leisure to read the full essay and, as he put it:
"...to correct some of the misrepresentations which have gone abroad respecting two or three of the most important points of the Essay..."[4]
A Summary View ends with a defense of the Principle of Population against the charge that it:
"...impeaches the goodness of the Deity, and is inconsistent with the letter and spirit of the scriptures."
See main article Thomas Malthus for more.
This was Malthus' final word on his Principle of Population. He died in 1834.
[edit]Other works that influenced Malthus

Of the Populousness of Ancient Nations (1752) - David Hume (1711-76)
An enquiry into the Nature and Causes of the Wealth of Nations (1776) - Adam Smith (1723-90)
A Dissertation on the Numbers of Mankind in Ancient and Modern Times (1753), Characteristics of the Present State of Great Britain (1758), and Various Prospects of Mankind, Nature and Providence (1761) - Robert Wallace (1697-1771)
Essay on the Population of England from the Revolution to Present Time (1780), Evidence for a Future Period in the State of Mankind, with the Means and Duty of Promoting it (1787) - Richard Price (1723-1791).
Observations Concerning the Increase of Mankind, Peopling of Countries, etc. (1751) by Benjamin Franklin (1706-1790)