Book: Marx Western Playsets

taken from an Ebay link:

Marx Western Playsets - The Authorized Guide

Written by Jay Horowitz, while he was the owner of Marx Toys, Inc.
This unique 192 page hard covered book reveals for the first time the true factory records and information about those famous Marx Playsets loved by generations of American children. Relive the rermarkable artistry of the figures, details, superior quality, and real play value. Who in America would not recognize western sets such as the famous Fort Apache. This book includes:

Never-before-published original Marx photos;
Factory Specification Sheets
Product Glossies
Color photos
Introduction by Charles Marx
History of Louis Marx & Co., Inc.
Background on Louis Marx and brother David
Index of Marx Western Playsets
How to Manufacture a Playset
Glossary of Plastic Manufacturing Terms
Other interesting information taken from the Marx Archives.

And here is a listing of other places to buy it