Andrew Scull has a devastating critique of Foucault's scholarship in the latest TLS.
It must be said, though, that Foucault at his best is an extraordinary writer and thinker: I am more or less allergic to Foucauldianism, especially in its more literal-minded versions, but I find myself returning to particular bits of his writing very regularly. I'm thinking in particular of that amazing essay "What Is Enlightenment?", required reading in my opinion (some of my students have heard me rhapsodize about this piece!).
Here's my favorite part, a rousing call for Friday-morning thinking (Foucault's essay responds to Kant's of the same name):
This ethos [of permanent critique] implies, first, the refusal of what I like to call the 'blackmail' of the Enlightenment. I think that the Enlightenment, as a set of political, economic, social, institutional, and cultural events on which we still depend in large part, constitutes a privileged domain for analysis. I also think that as an enterprise for linking the progress of truth and the history of liberty in a bond of direct relation, it formulated a philosophical question that remains for us to consider. I think, finally, as I have tried to show with reference to Kant's text, that it defined a certain manner of philosophizing.
But that does not mean that one has to be 'for' or 'against' the Enlightenment. It even means precisely that one has to refuse everything that might present itself in the form of a simplistic and authoritarian alternative: you either accept the Enlightenment and remain within the tradition of its rationalism (this is considered a positive term by some and used by others, on the contrary, as a reproach); or else you criticize the Enlightenment and then try to escape from its principles of rationality (which may be seen once again as good or bad). And we do not break free of this blackmail by introducing 'dialectical' nuances while seeking to determine what good and bad elements there may have been in the Enlightenment.
We must try to proceed with the analysis of ourselves as beings who are historically determined, to a certain extent, by the Enlightenment. Such an analysis implies a series of historical inquiries that are as precise as possible; and these inquiries will not be oriented retrospectively toward the 'essential kernel of rationality' that can be found in the Enlightenment and that would have to be preserved in any event; they will be oriented toward the 'contemporary limits of the necessary,' that is, toward what is not or is no longer indispensable for the constitution of ourselves as autonomous subjects.
When I was eighteen I was totally in love with literary theory and I must confess that my favorite book of Foucault's was the luridly titled I, Pierre Riviere, Having Slaughtered My Mother, My Sister and My Brother (the verb in the original French is "ayant égorgé," isn't that delightful?!?). And though I cannot say that I ever had the passion for Foucault that I had for Deleuze and Guattari's Anti-Oedipus (a book I read the first semester of freshman year & that just blew my mind, I read it again and again and it sent me to a ton of books by and about schizophrenics, including Schreber and Laing and so forth, very good reading) or for Derrida's lovely "Signature Event Context", which helped me to think about the electric telegraph and technologies of writing when I was doing my senior thesis, it was quite possibly this book of Foucault's that set me on the path of realizing (and there were other books along the way, like Peter Linebaugh's The London Hanged, recommended to me by Simon Schama after an amazing seminar on writing narrative history in which we read everything from Thucydides to Michelet and beyond & which showed me why I had not gotten anything out of creative writing classes & why my own temperamental & intellectual formation meant that there were other better ways of learning about fiction-writing, even if they involved me beating my head against a wall as I doggedly revised an unpublishable novel for the eleventh time or whatever!) that I was going to write a historical novel about Jonathan Wild. So that's, you know, autobiographically important...