This monograph provides a comprehensive overview on a class of nonlinear evolution equations, such as nonlinear Schrödinger equations, nonlinear Klein–Gordon equations, KdV equations as well as Navier–Stokes equations and Boltzmann equations. The global wellposedness to the Cauchy problem for those equations is systematically studied by using the harmonic analysis methods.This book is self-contained and may also be used as an advanced textbook by graduate students in analysis and PDE subjects and even ambitious undergraduate students.Contents:Fourier Multiplier, Function Spaces Xsp,qNavier–Stokes EquationStrichartz Estimates for Linear Dispersive EquationsLocal and Global Wellposedness for Nonlinear Dispersive EquationsThe Low Regularity Theory for the Nonlinear Dispersive EquationsFrequency-Uniform Decomposition TechniquesConservations, Morawetz' Estimates of Nonlinear Schrödinger EquationsBoltzmann Equation without Angular CutoffReadership: Graduate students and researchers interested in analysis and PDE.