A pioneer in applying mathematical methods to crucial questions in biology and medicine has died. Jaroslav Stark was born near Prague on 17 June 1960 and came to England after the defeat of the Prague Spring period of liberalisation in Czechoslovakia.
He went to school in Britain and the US before graduating with a first in mathematics from Peterhouse, Cambridge.
He then moved to the University of Warwick for his doctorate, just when it was establishing itself in the vibrant new field of dynamical systems and chaos theory.
Professor Stark followed this up with postdoctoral positions in Warwick and Imperial College London, and then took a sideways step into industry and spent four years at GEC.
He returned to the academy in 1993 as a lecturer at University College London. He was promoted to reader in 1996 and professor in 1999.
He was already married to Kate Hardy, now professor of reproductive biology at Imperial, and his interests had begun to shift towards biological systems.
For the second time in his life, he was a pioneer in a major uncharted area of mathematical analysis.
It was at this point that John Elgin, professor of applied mathematics at Imperial, decided to set up a new group on maths and biology, and he knew that Professor Stark would be an ideal recruit.
"Jaroslav wanted to apply maths to real biological systems," he explained, "to get his hands dirty, and not use mathematical idealisations.
"He said that every biological system required its own mathematical model. The first step was to understand the system and decide on the maths you needed. And you had to be good at modelling the real world, which is more of an art than a science."
In order to pursue such interests, Professor Stark moved back to Imperial as a professor of mathematics in 2003 and became director of the Centre for Integrative Systems Biology in 2007.
His commitment to the study of "real biological systems", often with practical applications, was reflected in research on ovulatory disorders with his wife, on heart surgery with his father (a paediatric heart surgeon also called Jaroslav Stark) and later on malaria.
Professor Elgin recalled him as "an absolute delight, very honest and trustworthy, and opinionated in a good way, ready to argue fiercely on virtually any topic.
"Though not religious, he held to a Buddhist belief in balance and would bake his own bread overnight."
Professor Stark died of a brain tumour on 6 June 2010 and is survived by his wife and son Daniel.