Given my interest in Wikipedia, pseudo-science, and skepticism I'm fond of works which at least help us identify the implicit (social) concepts we invoke when we talk about knowledge, authority, and expertise. Evans and Collins (2007) Rethinking Expertise is an interesting treatment of the topic: well-written (though more explicit definitions of the terms would be useful), engaging (via examples from the literature on the sociology of science), and satisfying (solidifying some of the things I've been thinking myself).
In order to best understand the terms of their "Periodic Table of Expertises", I reproduce it in my (mindmap) notes with hypertext where appropriate. I thought I would share it here too. For those interested, but not yet convinced, there are a number of reviews [1,2], the one by Michael Lynch and a response from the authors are evidence of some of the theoretical differences in the Sociology of Science (i.e., the distance between the "ground" of actual practice and analytic categories).