Charles X. Carlson was a prolific artist and author of art instruction books in the 1940s. Here's a link to a portrait on a blog by his nephew. He was a founder of the Octoraro Art Association. Another link to a Chester County, Pa. post about Charles X. Carlson.
The original book at Amazon.com A Simplified Art Anatomy of the Human Figure: The Essentials of Anatomy for Students and Proffessionals with over 350 Drawings, and the Dover reprint Art Anatomy Simplified.
Pencil, Ink and Charcoal Drawing This Dover book combines 3 of the books.
Here are some samples from two of them.
The Simplified Essentials of Charcoal Drawing
Some covers of other books.
The Direct Technique Water Color Painting: Facts, Methods and Tricks Illustrated and Simplified
Simplified Pocket Art Anatomy
Simplified ink, pen and brush drawing (His art instruction series)
Constructive Animal Drawing
Charles X. Carlson books on Ebay.
Figure Drawing for All It's Worth (How to draw and paint)
Charcoal Nudes (Gateways Fine Art Series)
Art Anatomy Simplified
Simplified anatomy of the human figure;: A guide to drawing for students and artists,
Simplified Anatomy for the Comic Book Artist: How to Draw the New Streamlined Look of Action-Adventure Comics!