Dr. L. R. Kadiyali earned his Ph.D. in Civil Engineering in India and has over forty years of professional experience in Highway Engineering. Of these, nearly thirty years were spent in the Ministry of Road Transport and Highways, Government of India, where he rose to the position of Chief Engineer and was actively involved in the planning, improvement, and maintenance of the National Highway system.
Dr. Kadiyali pioneered the introduction of cement concrete roads in India beginning in 1985. Owing to his sustained efforts, several concrete pavement projects were undertaken across the country. He also served as an Adviser to the Cement Manufacturers’ Association.

Dr. B.S. Grewal (1928– ) was an eminent mathematician, educator, and author whose self-made academic journey began in post-independence India. A distinguished teacher, DRDO scientist, and Director of Scientific Evaluation, he earned a PhD from Delhi University and published 14 research papers. His landmark textbooks—especially Higher Engineering Mathematics—have shaped engineering education across 90+ universities worldwide.

Santosh Kumar Garg, former Superintending Engineer with the Delhi Government’s Irrigation and Flood Control Department, is a distinguished civil and environmental engineer. A University of Delhi Civil Engineering graduate (1969), he secured First Rank with record marks and multiple merit certificates. He contributed extensively to major water resources, drainage projects, and Delhi’s Master Plan of Drainage. Author of eight acclaimed textbooks, his works are widely used across engineering colleges, IITs, NITs, and internationally.

Er. R.K. Jain, author of this book on Renewable Energy Systems has been associated with Mechanical Engineering for more than 40 years. He started his career as Lecturer in Mechanical Engineering Department in REC, Kurukshetra. Then he joined Central Electricity Authority where he rose to the highest level of chairperson of the organisation. Presently, he is working as in consultant with World Bank. He was actively involved a design, developing compact layouts and also selection of suitable sites for the Thermal Power Plants.

He has vast experience in writing a number of books on Engineering subjects and also authored books like ‘The Art of Happy Living’ and ‘Lifestyle for Total Development’.