Other contributions: The authors gratefully acknowledge the contributions of the patients, physicians, and staff of the participating Kaiser Permanente clinics. Arndt Herz, MD, Mygnoc Nguyen, MD, Laura Prager, MD, Peg Strub, MD, Madelyn Weiss, MD, Clifford Yee, MD, and Kim Trood, RN, facilitated study implementation in their clinics. David Mannino, MD, Maryanna Sockrider, MD, DrPH, and Dennis Ownby, MD, served on the advisory committee and provided valuable counsel on the study design. Charles Quesenberry, PhD, served as biostatistician and Kaiser Permanente principal investigator following Dr Farber’s move to Texas. Linda Bertorello, RRT, Lisa Caine, RCP, and Veronica Luna coordinated the study implementation, recruited subjects, and conducted baseline assessments. Ms Bertorello and Ms Caine served as LET’S interventionists. Paulina Ayres, Karen Kriete, Andrea Norcia, Debbie Schide, and Jodi Thirtyacre recruited and assessed subjects. Nancy Brown, PhD, assisted with intervention development, interventionist training, and intervention quality control by reviewing audiotapes of intervention sessions. Kathy Stamm and Teri Slifer at the Palo Alto Medical Foundation Immunology and Infectious Disease Research Laboratory analyzed the urine specimens for cotinine and creatinine. Ai Lin Tsai and Jun Shan, PhD, assisted with data extraction, under the general supervision of Dr Quesenberry and Stephen Van Den Eeden, PhD, respectively. Shinu Verghase, Yinge Qian, and Qiwen Huang performed the data analyses. The support of the National Heart, Lung and Blood Institute and Project Officers Robert Smith, PhD, and Virginia Taggart, PhD, is gratefully acknowledged. This study was performed at the Kaiser Permanente Northern California medical centers and the Palo Alto Medical Foundation Research Institute.