When one ponders on the question ‘why did you decide to write this book?’, there are at
least two options. Firstly, that you felt that there was a need for a book of this type, and
that, however pretentious it might sound, you were the right person to write it.
Alternatively, you might argue that, having taught undergraduate and postgraduate courses
on the subject, you could share your teaching with others who might appreciate the fruits
of your experience in the area