Hal Draper's extremely long and expansive series "Karl Marx's Theory of Revolution" is definitely the highest point achieved so far in systematic exegesis of the work of Marx (and Engels). Totalling five volumes, a total of almost 3000 pages, Draper has provided the most clear, thorough and readable full overview of the entirety of the political thought of Marx. As a former Trotskyist involved with the Schachtmanites, Draper could be suspected of having a controversial editorial line, but in practice this is only very mildly the case, and he is generally very strict and accurate in sticking to the clear meaning of Marx himself. This is in particular made possible by the great care Draper takes to provide the historical and intellectual context for Marx' statements on the respective issues, so that it is always clear what Marx intended with his sometimes cryptic or diplomatically phrased letters, notes, and so forth.
By coincidence this volume, the second in the series, bearing the title "The Politics of Social Classes" was the first one I read of Draper's total work. As the title indicates, this volume deals in detail with the theory of class, class background, class movement, and so forth. Draper considers systematically the extant statements by Marx and Engels on the various classes relevant to their discussion: first of course the proletariat, its meaning and special status, then the petty-bourgeoisie, their nature and background, the peasantry, the 'mixed classes', the intellectuals (not an economic class but a sociological one that has often been important in Marxist discussions), and the bourgeoisie itself. He also deals with the various movements and forms in which they appear, such as trade unions and unionism, Proudhon and his supporters, Bakuninism and anarchism, bourgeois Radicalism, social-democratic reformism and so forth. Even the often ignored lumpenproletariat gets its proper overview.
Draper as always is clear, well-structured and as concise as possible in showing what Marx and Engels wrote about the precise status and meaning of these different groups. One of Draper's strong points compared to many other Marxologists is not just his thoroughness and relative objectivity, but also his great knowledge of the more obscure statements and letters by Marx and Engels, which are often overlooked in favor of the more 'canonical' ones but which can shed more light on the particular meaning of certain terms and ideas. Sometimes this means that there have to be rather long excursa about of themselves less interesting topics such as Lassalleans, Schapper, the fights in the First International, and the like, but often in these contexts Marx and Engels made statements (prompted by the events) that they did not otherwise address in their theoretical works. One of these is the use and meaning of the term "permanent revolution", which Draper analyzes in detail. Although this term has been of great importance for many Trotskyists like Draper for their own interpretation, here also Draper sticks wholly to the text.
Draper's excellent series should not be seen as an invitation to treat the thoughts of Marx and Engels as Holy Writ or as a canon of dogma from which no deviation is possible and upon which nobody can improve. Instead, it should be used as the most expansive existing reliable analysis of Marx's & Engels' thought as such, allowing us to see both where they were right and where they were wrong, and allowing their brilliant minds to inspire us, that we may improve upon their work and understand our own times better. Although Hal Draper did not live to see his series finished, he has done us all a great favor with this life's work.
Volume III deals with the concept of the dictatorship of the proletariat, as the title indicates. This book is less good than the other ones, being fairly repetitive and Draper here crosses the line regularly in going into too much detail, with a lot of polemics making the impression of being much ado about nothing. The greater part of the book is taken up by a very long and detailed discussion of the political differences between Marx and the followers of Blanqui, and the way in which the Blanquists like most other socialist sects at the time looked for a dictatorship of the proletariat because they thought the proletariat was the group to bring their particular sect to power, rather than because they supported proletarian class rule.
The author makes it very clear that, although the precise contexts in which Marx & Engels used the term changed over time from the post-1848 period to the period around the Paris Commune, they consistently intended it to mean the rule of the proletariat as a class. This as against the modern conception of dictatorship as a term, which understands it as necessarily a form of arbitrary rule by one individual, whereas Marx & Engels, according to Draper, would have used the meaning that was prevalent in the 19th century: the classical meaning of dictatorship, i.e. being invested temporarily with full powers (regardless of whether it's an individual or a group) in emergency situations, comparable to 'martial law' or 'emergency law' clauses in modern constitutions. Therefore, Draper says, Lenin's argument that it necessarily had to mean arbitrary rule by the leadership of the proletarian party, because that was obviously the meaning of the word "dictatorship", was wrong (although this doesn't necessarily imply Lenin's government as such was illegitimate or anything).
Of itself that doesn't really tell us much practically though - the question what form the class rule of the proletariat should take is not thereby resolved. Draper himself clearly has his own preferences, influenced by his Trotskyist-Schachtmanite background, but those don't really find any more support in the works of Marx & Engels than for example Lenin's interpretation did. It is useful that Draper puts the myth of Marx as a Blanquist to rest, and he shows very well how the threat of "Blanquism" as some sort of big evil was used by reformist socialists against anyone actually revolutionary, but that is a little thin in content for so big a volume. Fortunately, the series continues better with Volume IV.
(Since Amazon thinks II and III are different versions of the same book, I have to edit in my review of volume III here.)