The Roaring Twenties, age of jazz and flappers, Model T Fords and Hollywood movie stars, was also a time when for millions the bulky catalogs of Montgomery Ward or Sears, Roebuck were a substitute for the window displays of Paris or New York fashion shops. Buying clothing through the mails had become an American institution, and entire families were often dressed via the U.S. Post Office. More conservative than the up-to-the-minute fashion shops,...