There are many reasons to read this book, not least because it is fascinating to the point of being slightly disturbing. You might want to know what neuroscience knows about how memory works. You might wonder why this strange ability to conjure the past evolved. You might also be curious about a book by two Norwegian sisters — one a neuroscientist (Ylva) and the other a novelist (Hilde). Or you might just want to improve your memory. If so, the authors have bad news. Memory does not work like the heart and lungs. No matter how many “brain-training” apps you download, you cannot give your memory a workout and make it fitter, overall.