I will discuss the Hrushovski-Kazhdan integration theory, which is a major development in the theory of motivic integration. I will first present the fundamental constructions in this theory (homomorphisms between various Grothendieck rings). Then i will define the Fourier transform and discuss its basic properties. The theory of definable distributions will also be discussed. In the end, as an application, I will show that the Weil representation exists on the Schwartz space.