I'm in the process of reviewing Erosion, a book I opened with high expectations that ultimately rewarded my confidence; I chose the latter expression with care. The book started slowly - I often closed the work and turned to something different each time I finished an essay. However, I never gave serious consideration to stopping, and after some fits and starts I ended up finding a groove that brought me through the second half of the book at a much faster rate than the first.
I mention this because I think my experience adds an unusual but important perspective to common reading advice - you should give up on a book if it doesn't grab you from the start. I don't disagree with it at all, in fact I think this is great advice because I suspect a lot of people stick with dull books for too long, which is both a waste of time and a possible deterrent to future reading, but I also worry about those great works that are tossed aside because of a few sluggish pages at the beginning. My suggestion for those who like to sample the early pages before committing is to add a small research element first - just a few minutes should be enough time to get a sense of the book before you start - because from my experience books with uncommonly positive receptions tend to live up to the billing, but accolades don't insure against a slow start. It's a bit like having to look at a resume before bringing candidates in for interviews - if you have a good sense of underlying qualifications, you'll make better assessments of what you see once you start the actual process.