So, I have the book "The First Five Pages" by Noah Lukeman (who also wrote an amazing book on punctuation called "A Dash of Style"--I recommend it to everyone) and while I have yet to read Five Pages, I can tell, through context clues, that the first five pages of your manuscript are important. [I will be reading this book soon.] I also think that, for me, the first five lines of a story, particularly a genre story, are equally as important. I'm not talking about the first five lines of a published book, I'm talking about unpublished, amateur writing--of people longing to be published. For example, my fellow writers on autonomy.com (a new site that I'm uploading stories too for feedback). I know whether or not I want to "watch" or "back" a story within the first few lines.
Anyway, this was my observation of the moment. Thought I'd share.