“Why Endless Theory of the Universe (Complete Unified Theory)”? The unified theory is most important theory in the scientific world. The scientists were trying this theory since 1873 when the attempts have been made by James Clerk Maxwell on electric and magnetic forces which indicated ---- the forces are interlinked. He described UNIFIED THEORY now called “Electromagnetism”. Einstein spent most of the later years searching for unified theory, but time was not ripe enough to establish his phenomena. Weinberg-Salam tried for Unified Theory also. They unified the electromagnetic, strong and weak forces called the GRAND UNIFIED THEORY (GUT) where they did not include gravity. Many scientists like Royer Penrose (Theory of Singularity), Stephen Hawking, and others scientists worked on the Unified Theory and the efforts were continued from their own choice of thinking. But not succeed till now. Unified theory means single theory. It can explain the internal functions of matter and applicable from particle to the universe. Nirmalendu Das works hard on the subject. The scientists, researchers, thinkers, teachers, students may entire into this new field to do work.