For over 40 years, the tech industry has been working to attract more women. Yet, women continue to be underrepresented in technology jobs compared to other professions. Worse, once hired, women leave the field mid-career twice as often as men. In 2013, Karen Holtzblatt launched The Women in Tech Retention Project at WITops.org, dedicated to understanding what helps women in tech thrive. In 2014, Nicola Marsden joined the effort, bringing her extensive knowledge and research on gender and bias for women in tech. Together with worldwide volunteers, this research identified what helps women thrive and practical interventions to improve womens experience at work. In this book, we share womens stories, our research, relevant literature, and our perspective on making change to help retain women. All the research and solutions we share are based on deep research and user-centered ideation techniques. Part I describes the @Work Experience Framework and the six key factors that help women thrive: a dynamic valuing team; stimulating projects; the push into challenges with support; local role models; nonjudgmental flexibility to manage home/work balance; and developing personal power. Employees thinking of leaving their job have significantly lower scores on these factors showing their importance for retention. Part II describes tested interventions that redesign work practices to better support women, diverse teams, and all team members. We chose these interventions guided by data from over 1,000 people from multiple genders, ethnicities, family situations, and countries. Interventions target key processes in tech: onboarding new hires; group critique meetings; and Scrum. Interventions also address managing interpersonal dynamics to increase valuing and decrease devaluing behaviors and techniques for teams to define, monitor, and continuously improve their culture. We conclude by describing our principles for redesigning processes with an eye toward issues important to women and diverse teams.