This is a horrifyingly bad eReader. I cannot believe Cambridge University Press produced such a poor piece of software. On an iPad, you can only read in landscape orientation, and each chapter of the book I’m reading is one long, long, long vertical scroll. The typography of the mathematics is fuzzy and ugly… it’s apparently just a bitmap. After accidentally creating a bookmark in the wrong spot, I gave up after trying fifteen times to remove it because the popup menu disappears as soon as it appears. A PDF would be 10,000% better, but CUP doesn’t care about that because this garbage reader lets them lock up the book that I paid $70 for. I will never buy another book that uses Cambridge Spiral.