b'THE MARATHON SALESPERSON|13news and discoveries to their clientsa glimpse or a taste of what was until then, unreachable or unknown to their customers. Medicines and sci-entific cures often travelled along the merchant routes. The most prosperous merchants learned and understood the importance of the third di-mension of selling, the relationships with their buyers; as a result, their customers eagerly an-ticipated their arrival. These merchants were re-spected and appreciated.Most enduring principles are based on natu-rallaws.Thisrelationshipbetweenprinciples and natural laws is easier to understand when we examine a fundamental natural law like gravity. From the beginning of time, gravity has affect-ed anyone and anything thats on earth and will continue to do so with or without our consent or understanding. Even without an understand-ing of its cause, our ancestors observed the ef-fects of gravity and then expressed the principle as Everything that goes up must come down. Then,intheseventeenthcentury,sometran-scendentaldevelopmentsoccurred.Thanksto the work of Sir Isaac Newton and others, we be-gan to understand gravity as a force that all ob-jects in the universe exerted. The more massive the object, the greater the force it exerted. Based'