The chapter discusses the progress in solving complex problems related to the phase rule, particularly in the study of silicate mixtures in igneous rocks at the Geophysical Laboratory in Washington. It highlights the importance of optical properties in glass, noting that optical glass is a crucial material for civilization and has led to the development of specialized glasses for various applications, such as X-ray and UV transparency. The book is praised for its thoroughness and comprehensive coverage of optical glass properties, with 36 optical glasses listed and their properties and compositions detailed. The section on Experimental Psychology by Robert S. Woodworth is also reviewed. The rapid increase in experimental psychology research has made older textbooks outdated, and Woodworth's book is seen as a comprehensive and fair representation of the field. Woodworth's approach is commended for its inclusivity and critical judgment, covering a wide range of experimental investigations without favoring any particular school of thought. However, the book is criticized for the lack of transparency in experimental methods and the insufficient reporting of raw data, which hinders the validation of conclusions. Despite these issues, the book is considered a valuable resource for students and researchers in the field.The chapter discusses the progress in solving complex problems related to the phase rule, particularly in the study of silicate mixtures in igneous rocks at the Geophysical Laboratory in Washington. It highlights the importance of optical properties in glass, noting that optical glass is a crucial material for civilization and has led to the development of specialized glasses for various applications, such as X-ray and UV transparency. The book is praised for its thoroughness and comprehensive coverage of optical glass properties, with 36 optical glasses listed and their properties and compositions detailed. The section on Experimental Psychology by Robert S. Woodworth is also reviewed. The rapid increase in experimental psychology research has made older textbooks outdated, and Woodworth's book is seen as a comprehensive and fair representation of the field. Woodworth's approach is commended for its inclusivity and critical judgment, covering a wide range of experimental investigations without favoring any particular school of thought. However, the book is criticized for the lack of transparency in experimental methods and the insufficient reporting of raw data, which hinders the validation of conclusions. Despite these issues, the book is considered a valuable resource for students and researchers in the field.