I am relatively new to the work of Foucault but (despite the arguments I have read elsewhere regarding whether he was essentially humanist or anti-humanist in orientation) it seems to me that his project here, an early one, was that of humanising the history of madness, or rather, bringing into the humanity of modern discourse the rather inhuman and widely divergent historical discourses on madness. We start at a massive remove from the modern discourses of mental health but trace a discernable path through historically changing social values and (what was later called) epistemes to reach it.
Foucault is very free with his style in this work and the tempo changes to accomodate different historical moods, as if he is in some kind of empathy or zeitgeist with the periods he lights up for us.
I wouldn't say that this is a pleasant read, since it deals with the harsh realities of confinement and the treating of inmates as animals - or less than - in some periods of time, but it feels very much like a necessary read, for anyone wondering how the medical perspective on madnes has become so hypostasised and final. In this respect the work is part of the bigger "archeology" of Foucault's other writings (which I am now undertaking). So, I guess I can conclude about this work, it definitely got me interested in a bigger picture and opened me to the significance that history plays behind the scenes of everyday life. Not light reading, but definitely worthwhile.