[4][5] In November 1944, after studying U.S. statistics, signing a book contract with a publisher and a second contract under which Reader's Digest would publish excerpts while he was still writing,[6] and sending a list of questions and interview requests to the governor of every state,[7][8] he set out to tour the country and interview its prominent citizens, including business leaders, politicians, writers, and academics.

His celebrity status not only gave him unusual access to many prominent people, but it also caused his travels to receive a great deal of public attention.

[10] An external event that did slow the process of writing the book was the fatal illness of Gunther's teenage son Johnny.

[11] Inside U.S.A. grew much longer than originally planned, which presented a problem because paper was in short supply in the postwar period.

[14] In a three-page profile of California governor Earl Warren, he described him as "honest, likable and clean" and someone "with the limitations of all Americans of his type with little intellectual background ... or coherent political philosophy" who would "never set the world on fire".

"[5]) Inside U.S.A. was the Book-of-the-Month Club main selection for June 1947 and ranked third among the best-selling nonfiction books in the U.S. for the full year.

[19] Gunther intended to write a companion book, to be titled Inside Washington, focused on the nation-scale problems, personalities, and institutions of the U.S.

He never completed the second book, because of the amount that would be required and because he could not decide how best to coordinate the publication timing with the quadrennial cycle of presidential elections.