|Left: the 1935 four volume English translation set of Italian engineer turned socioeconomist Vilfredo Pareto's 1912 Treatise on General Sociology. Right: the 1963 four volumes bound as two set by Dover edition (Ѻ) of the same.|
Pareto states his aim in the opening paragraphs of his Treatise as follows: 
“My wish is to construct a system of sociology on the model of celestial mechanics, physics, and chemistry.”
In 1912, Pareto finished his four volume book. Owing to a delay, as a result of the outbreak of WWI, as English political science historian Samuel Finer reports, it was not published until 1916.  The original Italian version was published in English in 1935 as a four volume set The Mind and Society; then later as a four volumes bound as two set by Dover (Ѻ) in 1963.
In the 1920s, the Italian version of the book, Trattato di Sociologia Generale, was making the rounds at Harvard, and thus forming the so-called Harvard Pareto circle (1932-1942), centered around American physical chemist turned biochemist Lawrence Henderson, which worked to shape American sociology in an alternative fashion to that of the then popular Marxian sociology. Henderson gave the following reduced synopsis of Pareto's treatise:
“The social system makes its appearance on page 1306 of Pareto’s book. It has been preceded by a painstaking choice, discrimination, description, and classification of its elements. The first quarter of the book, a study of the non-logical actions of men, leads up to the demonstration that no other elements of the social system are more important than the sentiments. The last half of the book is synthetic, but like all the rest it is enriched with a profusion of diverse and well-chosen facts. Pareto works up to his system, then defines it, and finally tests it in a survey of important aspects of the history of Europe. We can no long follow him here, for these eight hundred pages are incompressible.”— Lawrence Henderson (1935), “Pareto’s Science of Society” 
Notable and now famous Pareto concepts of: an economic agent as a “homo economicus”, circulation of elites, Pareto principle, among others, supposedly, are found in or derive from Pareto’s Treatise.
The following are noted excerpts from Pareto's Treatise:
“Sociology has hitherto been almost always expounded dogmatically. Let us not be deceived by the name of positive given by Comte to his philosophy; his sociology is as dogmatic as Bossuet’s Discourse on Universal History. The religions of the two men are different, but they are religions; and it is religions that we find in the works of Spencer, of De Graef, of Letourneau, and of innumerable other authors.”— Pareto (1912), Treatise on General Sociology (§6) 
|The original two-volume set (Ѻ) of Pareto’s Trattato di Sociologia generale (1916).|
The following are related quotes:
“And now the astonishing and perturbing suspicion emerges that perhaps almost all that had passed for social science, political economy, politics, and ethics in the past may be brushed aside by future generations as mainly rationalizing. John Dewey has already reached this conclusion in regard to philosophy. Veblen and other writers have revealed the various unperceived presuppositions of the traditional political economy, and now comes an Italian sociologist, Vilfredo Pareto, who, in his huge treatise on general sociology, devotes hundreds of pages to substantiating a similar thesis affecting all the social sciences. This conclusion may be ranked by students of a hundred years hence  as one of the several great discoveries of our age.”
“Pareto’s Trattato di Sociologia Generale is the hardest boiled book I have ever read. Three times, since I passed my puberty, has my mind been made over. Once by a nexus of which Henry Adams was the center, once by a matrix of which Frazer burned brightest, and once by a long study of genetics and evolution. Pareto is doing the job a fourth time, and far more vitally than any others.”— Bernard DeVoto (1928) 
“If we are to speak of Pareto’s treatise as a seminal book, we must use the epithet in the sense in which we apply it to Newton’s Principia. No revolution can follow it, except a revolution in the methods of the social sciences. That revolution is already in its first stages in Italy and in France, and my yet spread to England and to America.”— Andrew Bongiorno (1930). “A Study of Pareto’s Treatise on General Sociology” 
“Pareto’s Treatise is a work of genius.”— Lawrence Henderson (1935), Pareto’s General Sociology: a Physiologist’s Interpretation 
“Pareto’s monumental work, Trattato di Sociologia Generale, lies before us as the most massive and impressive statement of the mechanistic conception of social life.”References— Werner Stark (1962), Fundamental Forms of Social Thought 
“In my last three years DeVoto was my tutor in my field of English literature, with whom I met once a week to discuss my reading. Henderson had urged the Sociologie on DeVoto, as he urged it on everyone; DeVoto in turn urged it on me, not because it was sociology but because it might clear a lot of nonsense from my mind.”— George Homans (1962), “Autobiographical Introduction” 
1. (a) Pareto, Vilfredo. (1935). The Mind and Society: Trattato di sociologia generale (Volume One) (chemistry, 24+ pgs; physics, 15+ pgs; thermodynamics, 2+ pgs). AMS Press.
(b) Pareto, Vilfredo. (1935). The Mind and Society: Trattato di sociologia generale (Volume Two) (chemistry, 1+ pgs). AMS Press.
(c) Pareto, Vilfredo. (1935). The Mind and Society: Trattato di sociologia generale (Volume Three) (chemistry, 8+ pgs; physics, 7+ pgs; thermodynamics, 2+ pgs). AMS Press.
(d) Pareto, Vilfredo. (1935). The Mind and Society: Trattato di sociologia generale (Volume Four) (chemistry, 8+ pgs; physics, 4+ pgs; thermodynamics, pg. 1461; molecules, 7+ pgs). AMS Press. .
2. Stegner, Wallace E. (2001). The Uneasy Chair: A Biography of Bernard DeVoto (Pareto, 26+ pgs; course, pg. 82; derivation, pg. 110; §: Seminar on Pareto, pg. 138-43; three times, pg. 138). University of Nebraska Press.
3. Stark, Werner. (1962). The Fundamental Forms of Social Thought (quote, 125). Routledge.
4. (a) Finer, Samuel. (1966). “Biographical Summary”, in: Vilfredo Pareto: Sociological Writings (selected and introduced by: Samuel Finer; translated by Derick Mirfin) (§2, pgs. 9-12). Frederick A. Praeger.
(b) Samuel Finer – Wikipedia.
5. Pareto, Vilfredo. (1916). Treatise on General Sociology (§20, pg. 16). Publisher.
(b) Stark, Werner. (1962). The Fundamental Forms of Social Thought (quote, 126-27). Routledge.
6. Bongiorno, Andrew. (1930). “A Study of Pareto’s Treatise on General Sociology” (abs) (quote, pg. 351), The American Journal of Sociology, 36(3):349-70.
7. Homans, George. (1962). “Autobiographical Introduction”, in: Sentiments and Activities: Essays in Social Science (pg. 3). Transaction Publishers, 1988.
8. Henderson, Lawrence J. (1935). Pareto’s General Sociology: a Physiologists Interpretation (pg. 59). Harvard University Press.
9. (a) Henderson, Lawrence. (1935). “Pareto’s Science of Society”, Saturday Review of Literature, 25:3-4, 10, May.
(b) Barber, Bernard. (1970). L.J. Henderson on the Social System (§4:181-90; quote, pgs. 185+187). University of Chicago Press.