In the history of sociological thought Veblen was one of only few economists who sought to integrate questions of class, gender and ethnicity into economical analysis. This attempt seems to make his thoughts relevant in sociology, not economics, until today. A Survey of sociological opinion by Robert A. Jones and Sidney Kronus (from 1975) shows his relevance, better: the relevance of his ideas, quite good: Relevance (A Survey of Recent Opinion).

Brief summary of Veblen's main thoughts
Esp. in sociology from: Coser, Lewis A. 1977 [1971]. Masters of Sociological Thought: Ideas in Historical and Social Context. (New York: Harcourt, Brace, Jovanovitch, pp. 263-274).

• cultural evolution
• social change
• social evolutionism

Extracts from the prefaces of the following books.

The Theory of the Leisure Class (1899)
"It is the purpose of this inquiry to discuss the place and value of the leisure class as an economic factor in modern life" ... "Some attention is ... given to the origin and the line of derivation of the institution, as well as to features of social life that are not commonly classed as economic." ... "At some points the discussion proceeds on grounds of economic theory or ethnological generalization ... The data employed to illustrate or enforce the argument have by preference been drawn from everyday life, by direct observation or through common notoriety, rather than from more recondite sources at a farther remove." ... "Such premises and corroborative evidence as are drawn from remoter sources, as well as whatever articles of theory or inference are borrowed from ethnological science, are also of the more familiar and accessible kind and should be readily traceable to their source by fairly well-read persons."

The Theory of Business Enterprise (1904)
"In respect to its point of departure, [that] ... inquiry into the nature, causes, utility, and further drift of business enterprise differs from other discussions of the same general range of facts ... The point of view is that given by the business man's work, - the aims, motives, and means that condition current business traffic. This choice of a point of view is itself given by the current economic situation, in that the situation plainly is primarily a business situation. An ... examination of the ramifications and consequences of business enterprise and business principles would feasible, and should give interesting results. It might conceivably lead to something of a revision (modernization) of more than one point in the current body of economic doctrines. But it should apparently prove more particularly interesting if it were followed up at large in the bearing of this modern force upon cultural growth, apart from what is of immediate economic interest. This cultural bearing of business enterprise ... belongs rather in the field of the sociologist than in that of the professed economist; so that the ... inquiry, ... sins rather by exceeding the legitimate bounds of economic discussion on this head than by falling short of them. ... it is said that the features of general culture touched upon in these chapters bear too intimately on the economic situation proper to admit their being left entirely on one side."

The Instinct of Workmanship and the State of the Industrial Arts (1914)
"[That] ... essay attempts an analysis of such correlation as is visible between industrial use and wont and those other institutional facts that go to make up any given phase of civilisation. It is assumed that in the growth of culture, as in its current maintenance, the facts of technological use and wont are fundamental and definitive, in the sense that they underlie and condition the scope and method of civilisation in other than the technological respect, but not in such a sense as to preclude or overlook the degree in which these other conventions of any given civilisation in their turn react on the state of the industrial arts.
The analysis proceeds on the materialistic assumptions of modern science, but without prejudice to the underlying question as to the ulterior competency of this materialistic conception considered as a metaphysical tenet. The inquiry ... accepts these mechanistic assumptions of material science for the purpose in hand, since these afford the currently acceptable terms of solution for any scientific problem of the kind in the present state of preconceptions on this head. ..."

Imperial Germany and the Industrial Revolution (1915)
"... The essay was projected before" World War I "came on, though the complexion of subsequent events has also doubtless had its effect on the particular direction taken by the argument at more than one point in the inquiry. The inquiry ... is concerned neither with the controverted merits of the international quarrel nor with the comparative force and probable success of either belligerent. Its aim is the less polemical one of a comparison and correlation between the German case on the one hand and the English-speaking peoples on the other hand, considered as two distinct and somewhat divergent lines of the cultural development in modern times; and the ground on which the inquiry runs is that afforded by the economic, chiefly the industrial, circumstances that have shaped the outcome in either case.
It aims to account for Germany's industrial advance and high efficiency by natural causes, without drawing on the logic of manifest destiny, Providential nepotism, national genius, and the like. ...It is believed, nothing of consequence has appeared in the way of a theoretical inquiry into this Imperial era and the run of its industrial affairs, although many scholarly and workmanlike studies have presented the run of the facts from one point of view and another.
There is of course no intention here to impart information on the history of this period, whether political or economic and the historical information made use of as material for argument is of the commonplace kind familiar by common notoriety or from the standard manuals accessible to all readers. ..."

An Inquiry into the Nature of Peace and the Terms of its Perpetuation (1917).
"To any attentive reader of Kant's memorable essay ... 'Zum ewigen Frieden' ... it will be apparent that the title of the following inquiry ... is a descriptive translation of the caption under which he wrote." ... "The aim and compass of any disinterested inquiry in these premises is still the same as it was in Kant's time; such, indeed, as be in great part made it, - viz., a systematic knowledge of things as they are. Nor is the light of Kant's leading to be dispensed with as touches the ways and means of systematic knowledge, wherever the human realities are in question.
Meantime, many things have also changed ... Among other changes are those that affect the direction of inquiry and the terms of systematic formulation. Natura daedala rerum is no longer allowed to go on her own recognizances, without divulging the ways and means of her workmanship. ...
The quest of perpetual peace at large is no less a paramount and intrinsic human duty today than it was, nor is it at all certain that its final accomplishment is nearer. But the question of its pursuit and of the conditions to be met in seeking this goal lies in a different shape today; and it is this question that concerns the inquiry which is here undertaken, - what are the terms on which peace at large may hopefully be installed and maintained? ... And the answer ... is here sought not in terms of what ought dutifully to be done toward the desired consummation, but rather in terms of those known factors of human behavior that can be shown by analysis of experience to control the conduct of nations in conjunctures of this kind."

The Vested Interests and the State of the Industrial Arts. (1919)
"... The aim of these" (collected) "papers is to show how and, as far as may be, why a discrepancy has arisen in the course of time between those accepted principles of law and custom that underlie business enterprise and the businesslike management of industry, on the one hand, and the material conditions which have now been engendered by that new order of industry that took its rise in the late 18th century, on the other hand, together with some speculations on the civil and political difficulties set afoot by this discrepancy between business and industry."

Absentee Ownership and Business Enterprise in Recent Times. The Case of America (1923)
"[This] .. essay is an inquiry into the economic situation as it has taken shape during this (twentieth) century, particularly as exemplified in the case of America. Its aim is an objective, theoretical analysis and formulation of the main drift, as determined by the material circumstances of the case, including the industrial arts, and by the dominant institution of absentee ownership, including the use of credit. This analysis and formulation occupies Part II of the essay. ...
Part I of the essay is occupied with a summary description of that range of economic circumstances and that sequence of economic growth and change which have led up through the nineteenth century and have come to a head in the situation of the past two decades; regard being had chiefly to the case of England for the earlier decades of the century and chiefly to the case of America for the later years. ..."