Path Integral Approach in Theoretical Physics talks about the path integral approaches involved in the field of theoretical physics. It includes pure functions, elliptic feynman integrals, multi-regge kinematics and the scattering equations. This book also discusses about l-functions for meromorphic modular forms and sum rules in conformal field theory, application of path integral for multi-field inflation, variational path-integral approach to back-reactions of composite mesons in the nambu–jona-lasinio model, dual representation for the generating functional of the feynman path-integral and boundary integral method for modelling vibroacoustic energy distributions in uncertain built up structures.