Kaku's book, "Parallel Worlds," addresses the big bang and why it may not be the beginning, but rather just another stage of the development of infinite multiple universes -- what's now called "M-Theory." If you're interested in non-academic books on Physics, I'd also recommend "Quantum: Einstein, Bohr and the great debate about the nature of reality." By Manjit Kumar. It's an amazing book, brilliantly written.