Now, some would say "Hey, it's a physics books, what do you expect?", but I like physics books, especially ones using as much humor as is in this one. Lederman takes an interesting approach here, looking at the entire "intellectual history" of the search for the foundation particles of the world, from Democritus' "a-toms" to the products of the current massive colliders, discussing the evolution of the theories and how they related to discoveries from the lab (Lederman, being an "experimentalist" makes many jibes at the "theoretical" side of the physics department). Unfortunately, this is yet another book written before Clinton pulled the plug on the SSC (although it's not as unrestrained as Kaku in its enthusiasm, it seems that Lederman knew that the SSC was in serious jeopardy from the new regime in 1992), so it does have some of that "breathless anticipation" of all these cool new discoveries that seemed to be just around the corner in the Bush 1 era.
So, what's this "God Particle"? Well, it takes Lederman 340 pages to get around to that. Surprise! (or not, to science readers or fans of the Lexx TV series) It's the much-written of "Higgs Boson". Why is the Higgs boson the "God Particle"? It embarrasses me to say I'm not sure ... though it does seem to be one of those "missing links" (I was going to say "along with the Top/Truth quark" but I just noticed that this was discovered last year!) that would allow for a nice pat "Theory of Everything" with tidy symmetries from the innards of hadrons up through macro-world effects like electro-magnetism. It probably has something to do with being a quanta associated with the "Higgs field" which, in theory, permeates every place in the universe at all times, and gives mass to all particles (which, I assume, eventually points to a way of merging gravity into the Standard Model), but I could be off on that.
Anyway, The God Particle is (despite my long drag through it), a very informative and entertaining book (if, of course, you like science). This does seem to still be in print via a paperback reprint edition, so ought to be available through your local bookseller, but you could also snag a "very good" copy of the hardcover for under a buck via the Amazon new/used vendors!