Paul Robert Fisher was born in Brisbane, Australia, in 1954. He began his scientific training at the University of Queensland where he studied as an undergraduate and subsequently as a research student. He graduated with a B.S. degree (honors, first class) in 1975 and an M.S. degree in 1978, having published the first molecular genetic studies of bacterial degradation of the herbicide 2,4D. He then moved to the Australian National University in Canberra where he conducted his Ph.D. studies on photosensory and thermosensory signal transduction in the multicellular migratory form (slug) of the cellular slime mould Dictyostelium discoideum. The next move was to the Max Planck Institute for Biochemistry in Munich, Germany, where he worked for 5 years on photosensory, thermosensory, and chemosensory responses in the multicellular and unicellular stages of the Dictyostelium life cycle. In 1985, he took up a position at La Trobe University where he remained until appointed to the Chair of Microbiology in 2004. In the 1990s, a serendipitous discovery resulted in a change in his research direction and led him to initiate the study of mitochondrial biogenesis and disease in Dictyostelium. In 2007, he was awarded the prestigious Australasian Science Prize for the discovery in his laboratory the Dictyostelium model; the cytopathology of mitochondrial disease is caused not by a lack of ATP but by the chronic activity of AMP-activated protein kinase (AMPK), an energy-sensing alarm protein. The mitochondrial disease studies led him naturally to a broader research programme using Dictyostelium to study neurodegenerative diseases, including Parkinson's disease as well as lysosomal and vesicle trafficking disorders such as mucolipidosis and Batten disease.