Measurement," possibly the most deceptively boring title I've seen for a likely wonderful treatment of mathematics (for both the student and professor alike).
What many of us especially look for in a 'popular' math book is not just a good or even great presentation of mathematical concepts/ideas, but an evocation of the very joy and wonder that math can render. All indications are that Lockhart has accomplished that in this new volume (I have only begun reading it, but from thumbing through the pages and perusing reviews, that is my expectation).
Here, a blurb from Publishers Weekly:
and an audio review here:
This volume is in some sense a sequel to the author's well-known 2002 essay/rant? (later made into book form) "A Mathematician's Lament," which brought Lockhart some notoriety with his critique of American K-12 math education; available from Google documents here:
Addendum: if you haven't read them before, here are 2 columns Keith Devlin wrote on Lockhart some years ago: