Everyone agrees that the opening to a book is critical. Some say it’s the first five pages, some the first 18 lines (the first page on a typical print book), and some will tell you that you have to grab the reader by the throat within the first sentence, or All is Lost.
Well, to be honest, if a reader is so flighty that they’re going to toss a book based solely on the first line, I’m not sure I want them anyway. The first page is trickier. I can see the case for putting something there that’s so compelling that a reader absolutely has to turn the page. It’s all very well for George R R Martin to stick a forty page prologue up front, full of characters who promptly die, dialogue that is deeply portentous but unintelligable, and events that will possibly be understandable three books later, if you’re lucky. Most of us won’t be given that much leeway by the reader.