The book of songs is available from two used dealers at Abebooks (www.abebooks.com) for $25-30.
There were two printings- the one put out by Agricultural Broadcasting, Chicago, 1931, is the one you are looking for. The other may have different content.

Lester McFarland and Robert Gardner were blind singers who met at a blind school and teamed up as a country duo, according to one of the book offerings.