This book has been thoroughly revised according to the syllabus of Semester-IV (2nd year's 2nd semester) students of all universities of Andhra Pradesh. The revised syllabus is being adopted by all the universities in Andhra Pradesh, following Common Core Syllabus 2015-16 (revised in 2016) based on CBCS. This book strictly covers the new curriculum for 2nd year's 2nd semester of the theory as well as practical.