This volume is now more than a decade old, and much has transpired since then. The MATLAB tools have evolved from scripts, to Apps and at present to Live code. The Live package is preferred because it combines text and equations with MATLAB code all in a single site. The results of that code, formerly shown separately, also appear in line and in this way the user can vary the parameters of the specific problem and explore immediately how the solutions vary in response. For this reason, the Live scheme is used exclusively in this edition. The physics landscape has also evolved in the last decade. The Nobel prize in 2006 rewarded the discovery of small perturbation in temperature, at the parts per million level of the extreme isotropy of the Cosmic Microwave Background (CMB). The basic isotropy is now thought to indicate a period of rapid expansion of the Universe, called "inflation". With those discoveries, there has been more emphasis on astrophysics and cosmology, which contributes to advances in physics over the last decade. These changes have been reflected in the problems which are explored in this volume.