Marketing is huge and not to mention that since the explosion of the web, the marketing landscape is changing rapidly. No one can really define its boundaries. Thus, it is hard to pinpoint one book that you should be reading in order to improve your knowledge on the subject.

The New Rules of Marketing and PR is a good book for you to get started with but as mentioned, it does not cover everything about marketing that are out there. Thus, you should move into certain areas of marketing such as online marketing, direct mail, call calling, communications, email marketing, etc. before deciding which book to get.

In addition to books, I would recommend you to subscribe to blogs like SmallBizTrends, Hubspot, Duct Tape Marketing and of course my small business advice blog to stay updated with trends and tips when it comes to marketing for businesses.