The author describes research begun to improve waterproofing (during manufacture) of World War II army shoes, while leaving them permeable to water vapor. He experimented with ASAs reasoning that the polar carboxylic groups of the ASA molecules would react chemically with availabl amino groups of the collagen and the attached hydrophobic hydrocarbon chains of the ASAs would waterproof the leather fibers. Various leathers were tested: vegetable tanned leathers needed a pH between 3.0 and 3.5, favoring the chemisorption theory. The author presents a method for distributing in moist leather (during manufacture) the small amount of ASA needed to prevent stiffening of the leather upon drying, mixed with high boiling petroleum naphthas and mineral oil (lubricant) which he claims is permanently bound by the ASAs. He refers to his treatments as the BAVON method. The author also discusses the hydrophillic character of some chrome tanned, fatliquored leathers and the inability of stuffed (heavily greased) or of silicone treated leathers to absorb and transmit water vapor. He states that most fats and oils in fat liquors are desirable only while leather is drying. -- AATA