Much of our understanding of the structure of matter including the existence of the atomic nucleus and the existence of quarks comes from analyses of scattering experiments. Our purpose in this part of QLB is to introduce the basic ideas of quantum scattering theory for the simplest case, the scattering of a spinless particle by a fixed target, and thereby give the reader sufficient background to read research papers and the many excellent texts on the subject. Goldberyer and Warson (1964), Landau (1996), Morse and Feshbach (1953), Newton (1966), Taylor (1972) and Weinberg (1995) are recommended for further reading. Monahan (1995) is recommended for the theory of scattering of two relativistic particles with spìn, scattering in relativistic three-particle systems and scattering in a relativistic two-body system where a third particle can be created. In the six chapters which follow, the quantum mechanics of a single spinless particle is reviewed in chapter 2, scattering states and Møller operators are defined and discussed in chapter 3, the scattering operator is defined and discussed in chapter 4, the 7 operator is defined and discussed in Chapter 5, standard methods for solving the scattering problem are given in Chapters 5 and 6 and extensions to complex momentum and energy and complex angular momentum are given in chapter' 7. A construction of a family of interaction potentials which are equivalent for scattering is given in Appendix A and some properties of Riccati functions which are important for solving the scattering problem are given in Appendix B.