To Sir, With Love.

In this biography, the life of William Hugh Isbister is traced through three continents, where he planted the seeds of academic surgery into a generation of leaders in colorectal surgery. This ultimately improved the care for thousands of patients. His last station in Saudi Arabia made a huge impact on the country. I hope this article inspires others to write about their mentors who were important in their development as surgeons and physicians. Short biographies of these important figures will serve as a valuable historical record for generations to come.

What I Know: The Value of Mentoring and Leadership.

Stuart Binder-Macleod, PT, PhD, FAPTA, the 51st Mary McMillan lecturer, is the Edward L. Ratledge Professor of Physical Therapy and associate vice president for clinical and translation research at the University of Delaware (UD). He served as the chair of UD's department of physical therapy for 16 years, and his research laboratory had more than 25 years of continuous National Institutes of Health funding, including major funding for projects involving the development and testing of treatment interventions for individuals demonstrating poststroke hemiparesis. A recipient of multiple honors from the American Physical Therapy Association (APTA) and its components, Binder-Macleod also served on the task force that created the American Council of Academic Physical Therapy, and he currently serves on the Board of Trustees of the Foundation for Physical Therapy Research.

Introducing new group leaders: Christina Towers.

Christina Towers discusses her search for a collaborative institute and why she chose the Salk, San Diego, to establish her lab studying autophagy in cancer. She shares her advice for applying, the importance of identifying what you want, tackling the perceived requirement for geographic mobility, and her hope to hire people who share her curiosity and love of asking questions.

The First Cardiac Anesthesiology Fellow, William A. Lell: A Brief History.

Fifty years ago, on August 1, 1971, William A. Lell became the first cardiac anesthesia fellow at Harvard's Massachusetts General Hospital (MGH) Department of Anesthesiology, training with the world's first group of anesthesiologists whose clinical practice, teaching, and research efforts were exclusively devoted to cardiac anesthesia. Lell's early interest in cardiovascular medicine and how mentors, particularly at the MGH, influenced his early career development are recounted. The challenges a young pioneer faced in establishing and maintaining an academic cardiac anesthesia program during the initial and rapid growth of an exciting new subspecialty are described. Dr Lell's experience emphasizes the importance of seizing new opportunities and establishing meaningful working relationships with colleagues based on mutual trust as fundamental to successful career development and research in a new medical subspecialty.

Perspectives on Geoff Burnstock as researcher, teacher and friend.

Geoffrey Burnstock, one of the most talented and brilliant scientists of his generation, was born on the 10th of May 1929 in London and died on the 2ndof June 2020, aged 91, in Melbourne (Australia). Geoffrey Burnstock started his research studies with an interest in the nerves controlling the guts of guinea pigs, and discovered a completely unexpected and ubiquitous signalling system mediated via extracellular nucleotides (the "purinergic theory"), which revolutionized our understanding of how cells communicate between each other. He made the highly controversial discovery that ATP (adenosine triphosphate), a molecule well known to biochemists for its role as a source of energy inside cells, could also transmit signals between them. Initially, his somewhat heretical theory, that did not fit conventional views, found considerable resistance in the scientific community. However, he continued to accumulate evidence in favor of his hypothesis, extending it to a variety of organs and systems and demonstrating a role for purinergic signaling in the cardiovascular, respiratory and nervous systems, and in the pathophysiology of pain, blood clotting, cell proliferation and differentiation, and immunity. For his entire life, he struggled to attract scientists to this new field and, finally, in the early 1990s, did evidence emerge that convinced the doubters, due to new molecular biology techniques making it possible to isolate and identify the cell surface receptors for ATP and its breakdown product, adenosine. His death clearly impacted a huge number of scientists who have lost their pioneering leader. In this Review, I will not talk of the many discoveries made by Professor Burnstock, nor of his enormous scientific contributions to the field and of the incredible number of prizes and public recognitions that he has received after his theory was accepted worldwide. Instead, I will share some personal memories on him as a teacher and scientist, and, most of all, as a loyal and reliable friend. Geoff was an extraordinary human being, always eager to collaborate and share data, never jealous of his findings and capable of learning even from young people. He was known for his enthusiasm, empathy and ability to motivate young scientists. I was lucky to meet him when I was still very young, and the collaboration and friendship that we established and maintained across the years has profoundly conditioned my professional and personal life. For me, Geoff was what in Italy we call a "Maestro", one of those leading figures who are fundamental not only for mentoring an individual's career but also their growth as a scientist and as a human being.

A genealogical approach to academic success.

We analyse academic success using a genealogical approach to the careers of over 95,000 scientists in mathematics and associated fields in physics and chemistry. We look at the effect of Ph.D. supervisors (one's mentors) on the number of Ph.D. students that one supervises later on (one's mentees) as a measure of academic success. Supervisors generally provide important inputs in Ph.D. projects, which can have long-lasting effects on academic careers. Moreover, having multiple supervisors exposes one to a diversity of inputs. We show that Ph.D. students benefit from having multiple supervisors instead of a single one. The cognitive diversity of mentors has a subtler effect in that it increases both the likelihood of success (having many mentees later on) and failure (having no mentees at all later on). We understand the effect of diverse mentorship as a high-risk, high-gain strategy: the recombination of unrelated expertise often fails, but sometimes leads to true novelty.