this book could not have been written without the encouragement and ideas of the hundreds of students in the doctoral-level Proposal Development course that I taught at the University of Nebraska-Lincoln for over 30 years. Specific former students and editors were instrumental in its development: Dr. Sharon Hudson, Dr. Leon Cantrell, the late Nette Nelson, Dr. De Tonack, Dr. Ray Ostrander, and Diane Wells. Since the publication of the first edition, I have also become indebted to the students in my introductory research methods courses and to individuals who have participated in my qualitative and mixed methods seminars. These courses have been my laboratories for working out ideas, incorporating new ones, and sharing my experiences as a writer and researcher. In addition, I want to thank my staff over the years in the Office of Qualitative and Mixed Methods Research at the University of Nebraska-Lincoln who have helped to conceptualize content in this book. I am indebted to the scholarly work of Dr. Vicki Plano Clark, Dr. Ron Shope, Dr. Kim Galt, Dr. Yun Lu, Dr. Sherry Wang, Amanda Garrett, and Dr. Alex Morales. In addition, I am grateful for the insightful suggestions provided by the reviewers for SAGE. I also could not have produced this book without the support and encouragement of my friends at SAGE. SAGE is and has been a first-rate publishing house. I especially owe much to my former editor and mentor, C. Deborah Laughton (now of Guilford Press), and to Lisa Cuevas-Shaw. My current editor, Vicki Knight, has been most supportive of my work and has encouraged me throughout the process. Thanks, Vicki! And I want to thank all the staff of SAGE with whom I have had a pleasure to work through the past 25 years. We have grown together and helped to develop research methods as a distinguished, worldwide field. At SAGE, I have also benefited from the contributions of reviewers to this fourth edition: Gilberto Arriaza, CSU East Bay; Heather J. Brace, Whittier College; RM Cooper, Drake University; Vanessa P. Dennen, The Florida State University; and Lois McFadyen Christensen, University of Alabama at Birmingham