Acknowledgements

I’d like to thank Portland State University Library for the support in developing this textbook. In particular, I want to thank Ms. Karen Bjork for her support and patience. I also would like to express my sincere gratitude to the reviewers of this book for their time and insights. Last but not least, I want to thank my son Eric for his continued interest in his mother’s work even as a busy teenager, and for the delightful and enlightening questions.