It's official: Planesrunner is an exhilarating read! It's a perfectly balanced tale of science and adventure, and I enjoyed it immensely. I am so glad I have the sequel ready to devour!My favourite aspect of the book is the world-building. Parallel universe and multiplicity are the main concerns of the novel, and when Everett's father, a theoretical physicist, finds a way to open gates into the these other worlds, and creates a map for them, Everett's life changes forever. Soon we're careening into an alternate London, where fossil fuels never took off, and steam generated electricity is main power source. And instead of aeroplanes, transportation over large distances is completed in ... airships! I loved it all, and I feel that this other world is tangibly different from ours. Sometimes authors create their parallel worlds with things that are too familiar, but McDonald gives it new cultures, a new history and even a new language (that was fun!)Another thing I really admire is how McDonald explains the science behind the multiple universes theory. This story is well grounded in physics, and all the concepts are very well explained. I'm in awe at how the author incorporates the necessary background without breaking from the action of the story - I didn't think the science was too heavy-handed, and the concepts are introduced clearly and concisely.Everett Singh is our main protagonist, a young boy with Punjabi Indian heritage and a passion for all things science. He's also a genius: he understands abstract scientific concepts naturally, and can apparently think in seven dimensions, and he's an amazing chef. Ok, so he's unrealistic, unbelievable, too perfect. But it somehow went with the story - I think everything else was so fantastical and awesome that I was able to overlook the fact that Everett is amazing at everything he does and doesn't have any discernible flaws. I'm biased though - I think I also just really enjoyed a protagonist whom I could relate to on a cultural level, and a lot of the commentary on Punjabi and Indian families rang true for me.Where Planesrunner shines is its secondary cast - the crew of the Everness. The crew of the Everness is led by Captain Anastasia Sixsmyth, a woman I instantly admired for her forthrightness and spunk. Her daughter, Sen Sixsmyth, is the pilot of the Everness, and an amazing, quirky girl. I really like Sen, but I found it weird that she automatically assumed that Everett was homosexual when he didn't display interest in her. I don't like that kind of thinking - 'you're not interested in me, so you mustn't bat for my team' - Sen can't seem to understand it might just be her. The rest of the crew is made up of the hilarious Bible quoting Sharkey, and the stoic, sort-of mysterious Mchynlyth, a Punjabi-Scot. The villain of the story, Charlotte Villiers, is by contrast almost cartoonish, with the author neglecting to allow readers to understand her at all.Disappointingly, Planesrunner doesn't really explore the idea of multiple versions of the same person running into one another. It's mentioned, but considering it's the very first thing mentioned int he blurb, I had expected more of an emphasis on this aspect of the multiple-universe theory.Overall, Planesrunner is an incredible read, and I recommend it to anyone who likes science fiction. I think the world building and amazing execution will impress many readers, and look forward to reading the sequel, Be My Enemy, soon.A copy of this book was provided by the publisher for review.You can read more of my reviews at Speculating on SpecFic.