Postcards Period (Undivided back), 1901-1907
In 1901, private publishers were allowed to replace the words “Private Mailing Card” with “Post Card”, which became standard henceforth. Premium German-printed postcards became very popular in this period. The backs of the cards were designated for an address only, and the message written on the fronts. Americans from all walks of life used postcards increasingly and the era is described as a “postcard craze”.