Here's a quick read on lactic acid. Pretty different take on it from what I've read before, in terms of the science. I like the bit at the end about how coaches more or less got everything right, even if science hadn't quite caught up with in explaining WHY they were right. There's something to be said for good old trial and error.
It seems that with any specific topic regarding our health and bodies, all we have to do is wait long enough and the generally-accepted thinking on it within the scientific community will change almost entirely. However, a lot of the essential truths of how to relate to your body and how to best take care of it have yet to ever change substantially. Soldier on.