Dr. Jo Handelsman is a Howard Hughes Medical Institute Professor in the Department of Molecular, Cellular and Developmental Biology at Yale University. Research in the Handelsman lab focuses on understanding the structure and function of microbial communities. She has served as a highly effective mentor of undergraduates and graduate students in her research lab, launching many faculty careers from among her students. Beyond her own research lab, Handelsman has mentored many women and minority faculty and students nationally and internationally. Dr. Handelsman's goals are to produce students who bring confidence, rigor, and ethical values to the range of scientific activities - experimental design, analysis, and communication. Dr. Handelsman co-founded the Women in Science and Engineering Leadership Institute (WISELI), an NSF-funded initiative to study and address the barriers to advancement of women in science. In this role, she developed programs that have strong mentoring components that have led to campus-wide changes. While at the University of Wisconsin, Dr. Handelsman developed a mentoring course and an accompanying book that are used to teach mentoring at more than 64 universities in the United States. The Wisconsin Mentoring Seminar is an 8-session course intended to help mentors improve their skills through reading, discussion, brainstorming, and mutual support with other mentors. She extended this work to women in Arab countries through a State Department initiative to advance women in science in Islamic countries. Her work on the "science of mentoring" has been used as the basis for mentoring programs for women and minorities at all levels of academic science. She continues to be a hands-on mentor while extending her mentoring hand to a global community of women and other underrepresented groups.