"I had been keeping an off eye on the advertising field, thinking I might become an idea man and a copywriter"

Carl Sandburg's quote recommends that he was interested in the advertising field and was considering a profession in it. He was seeking to end up being an "idea male" and a "copywriter," which are 2 crucial roles in the advertising industry. An "concept guy" is someone who comes up with creative principles for advertising campaigns, while a "copywriter" is someone who writes the copy for the advertisements. Sandburg's quote implies that he was keeping an eye on the advertising field and was thinking about a career in it. It also suggests that he was looking to become an innovator and an imaginative author in the field. His quote is a testament to his ambition and drive to pursue a career in the marketing market.