Brewer provides a remarkably concise summary of Marxist (and adjacent) thinkers on Imperialism from Karl himself to what he dubs the 'classical Marxist theory of imperialism' developed around the turn of the 20th century as well as the dependency theorists which predominated the radical 60's and 70's. Contra the other reviewers here, I found him for the most part to be pleasantly sympathetic to the many writers he covers, although the work certainly lives up to it's claim to being a 'critical survey'.
Brewer's initially focuses his wrath on 'under-consumptionist' theories which he ascribes to Luxemburg, Hobson, and Baran. The thrust of this approach is trying to prove that capitalism requires foreign markets to survive; he summarizes a simple version of as follows: "(1) monopoly increases the share of profit, and concentrates it into fewer hands; (2) a large fraction of monopoly profit is saved, so saving tends to increase; (3) domestic investment opportunities are limited (it is sometimes also argued that monopoly reduces investment), so saving tends to outrun investment; (4) excess saving produces a chronic lack of demand, unless some outlet is found; (5) capital export can provide an outlet for excess saving." Brewer argues that this ignores the introduction of more capital-intensive methods of production and economic growth which he believes the increased saving will create.
Much of the invective against Brewer must be prompted by his rather dismissive treatment of Lenin, despite his pre-emptive defense that his arguments are not a "criticism of Lenin, but of the orthodox Marxist tradition which turned it into a sacred text" and I'm inclined to agree with his assessment that his "pamphlet has been treated with a reverence it does not deserve." He brings attention to the fact Lenin's 'Imperialism' openly declares itself a popular outline, and serves merely as a synthesis of the ideas already developed by Hobson and Bukharin (who himself mostly repackaged & organized those of Hilferding). He points out that despite Lenin defining imperialism as 'the monopoly stage of capitalism' implying the various tendencies he outlines stem ultimately from the consolidation of monopolies, he fails to explain why. Lenin states capital export, is necessary because capitalism becomes 'over ripe' due to the 'backward stage of agriculture' and 'impoverished state of the masses' which indicates he concurs with Hobson's under-consumptionism but which Brewer says is in contradiction with the arguments he advanced against the Narodnik's in 'the Development of Capitalism in Russia' (who believed capitalism could not develop due to a lack of a home market owing to the poverty of the masses).
Brewer demonstrates Lenin's thinking was in stark contrast with later dependency theorists, focusing on his statement to the effect that capital export only arrests development in the advanced countries at the expense of "expanding and deepening the further development of capitalism throughout the world." He further indicts Lenin for introducing a form of apocalypticism into Marxism, where one sees crisis and the breakdown of capitalism around every corner crippling their analysis and making them unable to explain or respond to its continued survival. And yet, despite all the criticism, Brewer defends Lenin against Bill Warren (who he is otherwise in general agreement with) who charges him with introducing the belief that capitalism is unable to develop the countries of the third-world (he instead traces this idea back to the Comintern in the 1920s, and then identifies Paul Baran as being the first person to give it theoretical backing).
Partisans of dependency theory will take issue with Brewer as his sympathies obviously lie with the 'classical theory' that capitalism is perfectly capable to extending itself into the underdeveloped states, and especially with the thinking of Bill Warren who heralded imperialism as a progressive force. The statements Brewer makes in the conclusion are very much dated. He says that Marxists in the 60's and 70's predicted continued US dominance and saw little chance of underdeveloped countries improving their relative position, and that "both predictions look pretty doubtful now." He confidently asserts that "US hegemony in the capitalist world is clearly over, so the fiercely independent states of the Third World can play off one capitalist power against another," and yet in just over a year after the second edition of this work was published in 1990, the USSR would collapse and Japan would enter what we now call the 'lost decade'; American hegemony was triumphant. Likewise, after the 1997 financial crisis ended the rapid growth of the Asian tigers, not a single underdeveloped country has managed to achieve rapid growth besides China. While that example does indeed invalidate the dependency theorists (China did the very opposite of 'de-linking') one does wonder if people like Baran and Frank (who once subtitled a book 'Underdevelopment or Revolution') had a point when they said underdeveloped countries need to pursue socialism.
While the book is overwhelmingly devoted to examining other people's theories and poking holes in them, when Brewer resolves to make his own contributions they are very interesting. During his treatment of Arghiri Emmanuel (which was on the whole very respectful) he endeavored to construct his own model based on his that serves to reinforce Emmanuel's claim that high-wages beget high-wages. He introduces 'non-traded goods' into the model and uses them to explain how investment will flow into the high-wage countries (as they have to be produced locally) in order to meet the higher demand. Later on, he makes the very interesting observation that when Europe and America industrialized, the world economy was not integrated. Transport was expensive and risky, basic goods and means of production were produced locally, competition from abroad was limited, and capital was relatively immobile. This meant capitalist development created an independent bourgeoisie. Thus its highly dubious if industrialization on the pattern of Britain is even possible today; underdeveloped countries face stiff competition from the advanced centers, thus industrialization requires displacing imports or breaking into export markets, as opposed to the easy process of displacing primitive craft industries (as occurred in Europe).
Brewer does make a few errors I only caught because of my extensive prior reading of Lenin and Engels, which does make me wonder if he made similar errors concerning other thinkers which I missed. On P. 125 he says Lenin drawing on Engel's statements about the English working class becoming more and more bourgeois is inconsistent with his statement that "the economic possibility of such bribery, whatever its form may be, requires high monopolist profits" because at the time (1858) Britain was not dominated by monopolies. This was indeed made possible by monopoly; England's industrial monopoly worldwide. As Engels explains in his 1885 article 'England in 1845 and in 1885' "during the period of England’s industrial monopoly the English working-class have, to a certain extent, shared in the benefits of the monopoly." Likewise, on P. 131 he says Lenin "vehemently rejected any idea of ultra-imperialism", but in the introduction he penned to Bukharin's 'Imperialism and the World Economy' he says "Can one, however, deny that in the abstract a new phase of capitalism to follow imperialism, namely, a phase of ultra-imperialism, is "thinkable"? No... There is no doubt that the development is going in the direction of a single world trust that will swallow up all enterprises and all states without exception." Lenin simply believed the capitalist system would implode before then. On P. 198 he unconvincingly proposes (following Warren) that dependency theory emerged because it fulfills the interests of the third-world bourgeoisie (this is despite it's main proponents being western academics, such as Frank, Wallerstein, and the like).
Brewer's survey is indispensable for those trying to understand imperialism, as he quickly brings you up to speed with all the various theoretical approaches (and points out their flaws along the way), although in the 30 odd years since this works second edition one can easily see the issues with his conclusions.