Lynn White's Medieval Technology and Social Change is a fairly famous and important contribution to the study of technology. It is however a bit dated, I read it cause it was short and I found it for $3 in a used bookstore (it helped that I was $2 shy of a discount). For a more recent study of technology I'd recommend Mokyr's Lever of Riches, though as a more general study it has less to say specifically about the Middle Ages.
Back to White's book. There are three main parts, the first, on the importance of the stirrup to the development of feudalism, is basically discredited. What I've read on the topic indicates the advantage of the stirrup, while significant, isn't as great as implied here (and if heavy cavalry was basically dependent on it, how could Alexander's hetairoi have served as a hammer to the phalanx's anvil?) and its development largely took place on the steppe and not in dark ages France.
The second part, on agriculture and particularly the three field system was interesting, but again, dated. The three field system certainly greatly benefited agriculture and allowed both more population and greater non-agricultural specialization. Again though, like with the stirrup, other books I've read have stated that the advantages were lower than presented here and that there was more going on. Other developments, such as the horse collar, were also less influential than claimed because the versions they replaced didn't have as many problems as asserted here. A good discussion, but it overemphasizes the role of technology in social change, and understandable reaction to its downplaying before this book.
The last section, on mechanical power, I found far more useful. This is again dated, White claims guns were developed in the west while they have now been decisively identified as a Chinese development (I am planning a post on how late Eurocentrism stayed with us later, I still find it even in books from the 80s) for instance, but this chapter provides much more detailed discussions of medieval technology than I found in Mokyr's book (though Mokyr is an excellent source for what he does cover). Being highly interested in economic aspects, I found most interesting the discussion of medieval labor saving devices, not just grain mills but also "mills for tanning or laundering, mills for sawing, for crushing anything from olives to ore, mills for operating the bellows of blast furnaces, the hammers of the forge, or the grindstones to finish and polish weapons and armour, mills for producing pigments for paint or pulp for paper or the mash for beer, were to be found all over Europe." (White 89) The notion that machinery was not applied to production beyond luxuries before some sort of shift in the Dutch Republic is simply a pernicious myth. It was all over Europe, and the industrial revolution can't be explained in these terms. People have been using machinery for primitive production for more than a thousand years, and not just for luxury goods. Yet I still see this idea repeated (it was widely believed in the 19th century when research such as White's hadn't been conducted, things look simple when you don't know the complexities exist, go figure). Books like this need to be read just for this knowledge, if nothing else