In Selling the Invisible: A Field Guide to Modern Marketing (Texere, 2001), Harry Beckwith, a leading writer and speaker on marketing for service firms, provides great perspective and insight into marketing services. Also recommended are Beckwith’s later books, The Invisible Touch: The Four Keys to Modern Marketing(Texere, 2001) and What Clients Love: A Field Guide to Growing Your Business (Warner Books, 2003).