When faced with a reading assignment that seems above your level--whether it's a couple of pages, a short article or an entire book--it's easy to feel overwhelmed and like giving up. However, if you skim the material first, the assignment becomes much easier.
Focus first on the things you can understand and don't get bogged down in the difficult parts. Don't worry about skipping over passages that are really difficult. Even if you understand just 50% of the material, that will be enough to greatly increase your understanding on your second time through.