There is no magic about advertising agency service. Few advertising agents know, or ever can learn, the individual business of a client as well as the client himself knows it.
On the other hand, few manufacturers can have the agency's firsthand contact with hundreds of different selling methods, or develop the agency's corresponding breadth of vision. The very intensity of a manufacturer's specialization leaves him too little time to study and profit by the successful methods of other manufacturers. If positions were reversed, this broad, general knowledge of the advertising agent would be out of place. The manufacturer needs his intensive specialization to further his business. The advertising agent needs his broad, general knowledge of selling. The joint efforts of a competent manufacturer and an equally competent advertising agent accomplish the purpose of combining a high degree of specialization in the manufacturer's chosen field with a broad understanding of the most modern selling methods.
