Surprisingly undervalued books
Undervaluing Wittgenstein isn't really consistent with what I've read in American philosophy at least. If you go by objective metrics (which would be the <i>Moneyball</i> approach), he consistently tops the citation counts, and beyond that, is considered central to many areas. Probably only Heidegger gives him a run for most broadly influential 20th-century philosopher (though it's hard to compare directly, because they've been influential on quite different groups).<p>He's been particularly influential on analytic philosophy via Saul Kripke, among other interpreters. In popularity contests, he routinely gets voted #1 most influential philosopher in polls of academic philosophers as well, e.g. in a 1999 poll of mostly UK/US academic philosophers (<a href="http://commonsenseatheism.com/wp-content/uploads/2011/02/Lackey-What-are-the-modern-classics.pdf" rel="nofollow">http://commonsenseatheism.com/wp-content/uploads/2011/02/Lac...</a>) and in a Brian Leiter straw poll (<a href="http://leiterreports.typepad.com/blog/2009/03/so-who-is-the-most-important-philosopher-of-the-past-200-years.html" rel="nofollow">http://leiterreports.typepad.com/blog/2009/03/so-who-is-the-...</a>). The former one concludes that <i>Philosophical Investigations</i> is "the one crossover masterpiece in twentieth-century philosophy, appealing across diverse specializations and philosophical orientations".<p>An interesting question might be who is undervalued on those lists: is there someone halfway down, or not on the list at all, who should be near the top?