Mel Bay’s series of music education books with “chords in photo-diagram form”, or “picture & diagram form”, was first published in the 1950s, see an issue dated 1959. The series design shown here was introduced around 1961.
After the war, Bay was asked to write instructional material on the guitar for GIs wishing to learn music under the GI Bill. When he approached the three major music publishers in New York City, they turned him down, saying there was no future in the guitar. In 1947, he formed Mel Bay Publications and wrote the first book, The Orchestral Chord System for Guitar. This book is still in print under the title Rhythm Guitar Chord System. His Modern Guitar Method was written shortly after in 1948. After the success of Elvis Presley in the early 1950s, the guitar became more popular, helping to ensure the success of the company. For years Bay traveled from town to town, talking to guitar teachers and players, and showing them his publications. He claimed to have known every guitar teacher in America on a first-name basis.