In larger organizations, you'll find marketing and sales broken into two different, distinct departments. A lot of times large organizations view sales as a money making venture and marketing as an expense or even a money losing venture that they grudgingly have to do. Personally I look at sales as a subset of marketing. Marketing, in a big picture view, is putting on the best face for potential clients, peers, the media and the general public. This is extremely important, as a a side effect of sales. You want the customer not only to purchase your product or services, but you want them to be happy about having done so. You want them to look forward to the current purchase; to look forward to the next purchase. You want them to be happy. You want them to eventual be a source of testimonial and of kind words about your product and or service, and about your organization that you can pass along to other people who are thinking about doing business with your company. So what you need to think of is sales as kind of a subset of the marketing process.