A foundational text in experimental design and statistical methodology, "Planning of Experiments" by D. R. Cox stands as a seminal work that shaped modern scientific research practices. Cox's rigorous approach to designing experiments—covering factorial designs, randomization, blocking, and confounding—established principles that remain central to fields ranging from agriculture and medicine to engineering and social sciences. Published during a pivotal era in statistics, this book bridged theoretical statistical theory with practical laboratory application, enabling researchers to extract maximum information from limited resources. Cox's clear exposition of how to structure experiments before data collection transformed scientific methodology from ad-hoc observation into systematic, efficient inquiry. The work remains influential in graduate-level statistics education and continues to guide researchers seeking to minimize bias and maximize the validity of their findings.