People naturally look at the cover first. The cover sets the tone for the book. Book cover design has a huge impact on peoples purchasing decision. People will read the introduction to a book, but will still return to the cover. Take two books at a book stand, both with the same information, one has a great design on the cover, the other has no design, which do you think a buyer would choose?
Self publishers and publishers look to companies that can take a book and build a cover that will draw peoples attention. Great book cover designs increases sales and profits. It is important to choose a designer that you work well. If you are a self publisher, then you know what the book is about, and have a good insight into what the design might look like. A professional designer can take your ideals and give you a great design. When looking for a design company, be sure that you choose one that will work with you. Talk with the designer before deciding if the company is a right fit, and can give you the results you want for the cover of your book.
A good book cover design does increase sales, which increases profits. Be sure that your design portrays the book you have written. Choose a company that understands the importance of a good book cover design, and go for it.