Metaphysics, pure old-fashioned ponderings on the nature of the REALLY REAL, form the subject of this unflagging excursion by quantum physicist Herbert. It is not news that the world of the infinitesimally small has been riddled with paradoxes ever since Heisenberg established the Uncertainity Principle, and others provided the essential credentials for the dual nature--particle and wave--of quantum matter or ""quons,"" as Herbert calls them. Einstein forever fought the probabilistic implications of quantum theory and repeatedly debated Bohr, who stoutly defended what became known as the Copenhagen Interpretation, which held that ""entities""--fundamental particles--possess no dynamic attributes on their own; they gain attributes (e.g., mass, spin, charge) in the act of measurement. The investigator assumes a mask of divine ignorance before conducting measurements: ""The knowledge he lacks is simply not there to be known."" It was further agreed that a single unmeasured quon can take all paths open to it. ""No,"" say a number of latter-day mavericks who have come up with alternative realities. It is Herbert's pleasure to tick these off (along with amusing cartoon diagrams that offer other prospects of what's there when nobody's looking). In this context he invokes John Stuart Bell's theorem that any mode of reality must be non-local, i.e., that the behavior of the quon is affected by phenomena that are ""superluminal"": they travel faster than light. This aspect appeals to a number of current meta-quantum-physicists such as David Bohm, and others whom Herbert calls ""neorealists."" Herbert also discusses various ""proxy wave"" interpretations of John von Neumann and the many worlds idea of Paul Davies, among others. However, perhaps Richard Feynman has the last word (early in the book): ""I think it is safe to say that no one understands quantum mechanics. Do not keep saying to yourself, 'but how can it be like that?' . . Nobody knows how it can be like that."" Herbert makes an engaging try that should open discussion among students and colleagues, but just may leave even the most intellectually courageous lay readers lost in a superluminal fog.