Dr. Lothar Bernd Zimmerhackl died suddenly on 27 August 2010 leaving a void in both nephrology and paediatrics. We commemorate him as a man and as a medical leader who leaves a remarkable legacy of research accomplishments, and will be long remembered for his teaching and devotion to patients, to students, and to our profession. His professional achievements reflected his lifelong inclination towards committing deliberate acts of kindness and generosity. Dr. Zimmerhackl was born in Weinheim, a town in the northwest of the federal state of Baden-Wurttemberg in Germany, on 30 December 1952 and obtained his MD in 1982 at the University of Heidelberg, Baden-Wurttemberg, Germany. Since his student days, he detested shallowness and required meticulous work from his co-workers and colleagues. Theoretical concepts and new achievements in paediatrics have been mastered to perfection in his life. This was particularly evident already during his time as a research fellow in the laboratory of Prof. Dr. Michael Steinhausen, a renal physiologist and worldwide expert in the microcirculation of the glomeruli. His research interests were further developed at the Stanford University, where he received a postdoctoral fellowship research grant. Subsequently, he worked at the University Children's Hospital in Marburg from 1984 to 1988 and later at the University Children's Hospital in Freiburg, where he completed his training as a paediatrician and defended his Ph.D. thesis on ‘novel methods for the early detection of regional tubular disorders in childhood’. Later, he focused on the haemolytic uraemic syndrome, complement-mediated paediatric diseases and membranoproliferative glomerulonephritis, making enormous contributions in the understanding of these diseases and organizing national and international meetings on these subjects. Dr. Zimmerhackl’s deepest knowledge was in paediatric nephrology, but his interest and research extended widely through other paediatric fields, and he became an internationally recognized paediatrician and researcher. In 2002, he was appointed as Professor and Chairman of Pediatrics at the University of Innsbruck, Austria, a position he held until his death. Vergil’s line, ‘Felix, qui potuit rerum cognoscere causas’ (fortunate is he who is able to know the causes of things), found a resonance in Dr. Zimmerhackl’s life. As student of Dr. Wilhelm Doerr, he was fascinated by morphology and loved clinical pathology. In Innsbruck, we successfully established a practice of having a clinicopathologic meeting and issuing a preliminary report of paediatric renal biopsies just a few hours after biopsy. He was eager to know the results of the biopsy, and he favoured clinicopathological discussion shortly after the biopsy was performed in order to start therapy as soon as possible. Despite his many professional commitments and other interests, his first priority was his young patients and their families. We will remember Dr. Zimmerhackl as his own man. A common theme throughout his life was that regardless of his successes or failures, a man should be comfortable in his own skin. A severe self-critic, he dealt poorly with ignorance. His publishing alone made him famous, but his energies were also devoted to paediatric healthcare planning. Impulsivity was part of his character, and this aspect was quite known to many colleagues, and it has been sometimes misinterpreted as arrogance. Life goes forward, even in his absence, but the consolation is that he has been mentor of innumerable doctors and students, and his message should be memorable for future generations of doctors. Of course, this era of telemedicine and nanotechnology pathology seems to be changing radically, but technological triumphs do not negate the wisdom of Morgagni and Vesalius. We will see new achievements, and new diseases will be discovered, but his teaching and approach should not be forgotten. As a former colleague, mentor and friend, Dr. Zimmerhackl will be greatly missed. Recalling Dr. Zimmerhackl’s high level of morality and many scientific accomplishments, we are reminded of Goethes’ quotation: ‘The greatest happiness of the thinking man is in exploring what there is to explore and respecting the inexplorable’ (‘Das schonste Gluck des denkenden Menschen ist, das Erforschliche erforscht zu haben und das Unerforschte ruhig zu verehren’).