Leather has been used since ancient times as a protective material for clothing and shields, and it continues to play an important role in modern applications such as garments, footwear, accessories, upholstery, and industrial goods. One of the key factors determining leather quality and durability is its pH level, which reflects the effectiveness of tanning and dyeing processes. This book explains standard methods for measuring pH, both in solution and directly on the material, along with essential chemical analyses required during leather processing. It covers testing of water, curing and pretanning chemicals, tanning materials, and various tanning agents, helping readers understand how to assess leather quality and differentiate it from synthetic substitutes.