Many good ideas on mercenary reading here. Feel free to set aside the “rules” of front-to-back reading. Gotta participate actively and take what you need.
The work is an expression of the message, not the message itself. So forget everything but that message and how to apply it to your life. Dates, names, pronunciations–-they only matter in how they provide context for the lesson at hand.
You ought to ruin the ending–-or find out the basic assertions of the book–-because it frees you up to focus on your two most important tasks: 1) What does it mean? 2) Do you agree with it? The first 50 pages of the book shouldn’t be a discovery process for you; you shouldn’t be wasting your time figuring out what the author is trying to say. Instead, your energy needs to be spent on figuring out if he’s right and how you can benefit from it.