At the time of the Industrial Revolution, production was king. As long as a factory could churn out a bunch of stuff at a reasonable price, it was virtually guaranteed to sell. Sales and marketing were little more than icing on the cake.
Today, this situation has been turned on its head. Marketers and salespeople play an important, if not the most important, role in most businesses' survival and profitability. A mediocre product supported by a good sales and marketing team will usually succeed; an excellent product with bad marketing will generally sink.
Both sales and marketing are about how a company reaches out to the public. Sales are somewhat more direct and can be defined as the art of converting potential customers into actual customers. Marketing is somewhat broader and includes promoting a brand, advertising, and even the logistics of delivering products or services. Arguably, you can't understand one without some knowledge of the other...a good salesman or marketer is more than a fast talker who doesn't mind stretching the truth!
Aside from the general business subjects you'll take in any bachelor's program, a degree in sales and marketing will show you how to research and define customers' expectations and buying behavior. You'll also learn how promotions and advertising campaigns are designed and assessed. In most degree courses, you will work through numerous case studies to get a feel for the practical side of the sales and marketing game.
Increasingly, in both the United States and Europe, you can find sales and marketing degrees geared toward online media and business. Other specializations worth keeping in mind are foreign sales and business, and data science as this applies to market research.