This is the Second edition of the book "Engineering Mathematics Volume-IV (Complex Variables and Fourier Analysis)". This text book has been written strictly according to the revised syllabus (R-16) 2016-17 of B. Tech. II Year, First Semester students of Jawaharlal Nehru Technological University, Hyderabad. The treatment of all topics has been made as simple as possible and in some instances with detailed explanation as the book is meant to be understood with a minimum effort on the part of the reader. However, as Mathematics is a subject to be understood and practiced, the students are advised to practice the exercises.