I have bit the bullet and am attempting to get my head around the MPL library. I realize there is a book out by Messieurs Abrahams and Gurtovoy, I believe, but I thought I would tackle the boost documentation first. A few questions: 1) Is the documentation up to date ? 2) There are three separate documents to study, it seems, all giving information about the MPL library, a white paper circa 2002, a reference, and a mini-tutorial. Is the information in these in sync with each other ? The reason I ask is that the white paper/mini-tutorial mentions if_<> and apply_if<> but the reference does not mention them at all.Are they just understood intrinsic metafunctions that need no reference, or what ? If the former, are there more of these intrinsic metafunctions and, if co, what are they and what do they do ? 3) A number of the topics in the reference documentation mentioned in generalized overviews of the various sections have no specific links. Does this mean that they were never implemented ? Seems dubious in a number of cases. I would seriously like to figure out how MPL works and play around with it, but I feel stymied with what is in the boost docs.