*Cross-posted from Goodreads: https://www.goodreads.com/review/show/2068893278*

Michio Kaku’s Parallel Worlds is a book about the science behind the multiverse and parallel universes. And no, it’s not a bunch of mathematical equations and theoretical derivations. Rather everything is explained in classical Michio Kaku style, in layman speak.

I bought it 6 years ago as research material for my sci-fi novella project. When I first came across the multi worlds interpretation (or MWI) I was enthralled. I instantly knew that I wanted to write a story based on the concept.

Anyone who has read about quantum mechanics is familiar with the uncertainty principle, which states that it is impossible to accurately predict the position/momentum of a subatomic particle without directly observing it. Stated differently, a particle such as an electron exists in all possible positions at the same time! It’s as spooky as it sounds. Applied in Schrodinger’s Cat experiment it leads to the cat being dead AND alive at the same time. How’s that possible? According to the Copenhagen interpretation of quantum mechanics, it’s not. Rather the cat’s dead state and alive state are both “virtual” (temporary) until the box is opened to look at the cat, at which point the cat’s wave function collapses to one and only one state – dead OR alive.

MWI is one of the several interpretations of quantum theory that says all possible quantum states of an object or action actually exist/occur but in different ‘parallel’ universes. So our beloved Schrodinger’s cat can be both dead AND alive but in different universes. There’s no need for the wave function to collapse based on observation. If you found all of this confusing, don’t worry: it *is* confusing.

Anyway, the concept of parallel universes fit in well with an idea for a sci-fi work I had in mind at the time. So I wanted to learn about it in depth. On googling a bit, I stumbled upon Dr. Kaku’s book. (I haven’t been able to finish the novella, in case you’re wondering)

Although MWI is only briefly discussed in the book, it mentions a lot of similar theories and explains them in extraordinarily simple terms with vivid analogies and intriguing historical accounts. Dr. Kaku neatly weaves together science and philosophy to help his ‘unscientific’ readers make sense of bitterly complex physics behind the beginning and end of our cosmos.

The material gets difficult to comprehend at times, but that’s perhaps only because the physics of the very small and very large is excruciatingly complicated. It’s beyond common sense. Though I wish Dr. Kaku had spent a few extra lines to try to explain some difficult bits further.

Overall, I found the book to be immensely thought-provoking. It whets your curiosity and answers some of the most daunting questions.