Here are the books that I've either read, are on my list, or are sitting here waiting to be read on subjects like entrepreneurship, all things small business (e.g., sales, marketing), and social media.  This is a broad category indeed, but they are very related.  For example, entrepreneurs need to know about business plans and how to sell their ideas.  Another example is that small businesses need to know how to leverage social media tools, sites, and techniques.