Theory, Analysis and Applications by Dr. Dhirendra Kumar Jena is a comprehensive textbook designed for undergraduate engineering students across disciplines, integrating economic theory with practical decision-making tools. The book systematically covers foundational concepts such as demand, supply, and market structures, and advances to core analytical areas including cost analysis, break-even analysis, time value of money, capital budgeting techniques, and macroeconomic contexts like inflation and banking. Structured with learning objectives, solved numerical problems, exam-oriented questions, and real-world applications, it aims to bridge the gap between technical engineering knowledge and economic reasoning, making it both an academic resource and a practical guide for engineering decision-making.