Thank you to my wonderful wife Sayora whose steadfast patience and support makes her a midwife to this project. Further thanks go to Murray de Villiers of SAS South Africa for brokering the book and supporting the courses through which the material arose. As with all such books, the constant probing and constructive inputs of my students has been the book’s canvas. Further thanks go to my editorial team at SAS Publishing, and my family who helped in many ways.