Despite being written in 1997, Harry Beckwith’s Selling the Invisible continues to justify its subtitle of A Field Guide to Modern Marketing. When it was published, online marketing was in its infancy, yet the book still has masses to teach us about marketing service-based businesses. Divided into small, bite-sized sections, it’s wise, insightful and incredibly readable. Put simply, it’s a stone cold classic. Buy it now – you won’t regret it.