In Search of the Multiverse by John Gribbin Wiley HK$200
How many versions of you are there - one or millions? Some physicists believe that an infinite number of universes exist parallel to the one we live in.
These universes might only differ slightly from ours: for instance, one might contain a version of you with blue hair instead of black, or three thumbs instead of two. Or they could be entirely different universes with laws of physics completely at odds with our own.
In In Search of the Multiverse, John Gribbin sets out the arguments for the existence of such entities.
This may sound like a case of scientific imagination running riot, but it has been taken seriously in university physics departments since the turn of the millennium. That's because it's now the only theory than can explain why particles at a quantum level - that is, the atomic level and smaller - behave the way they do.
Gribbin's book is written for the layman reader, and he - rather amazingly - manages to explain a subject which is generally expressed in the language of mathematics without using a single equation.
In Search of the Multiverse starts with a basic introduction to quantum physics and then moves on to analyse the two main multiverse hypotheses: the 'many worlds' hypothesis and the 'cosmic landscape' hypothesis.