The “Cambrian Explosion” and the “Great Ordovician Biodiversification Event” are the two major adaptive radiations of the Phanerozoic. The Cambrian Explosion saw the apparently sudden appearance of all major metazoan phyla and the establishment of complex ecosystems. The subsequent Great Ordovician Biodiversification witnessed an exponential increase in diversity within animal phyla. The origins of this critical event, establishing the “Palaeozoic Evolutionary Fauna” which dominated the biosphere for the next 240 Ma, are complex and hotly debated. Exceptionally preserved biotas have an important role to play in our understanding of the Ordovican radiation, but their scarcity, and the fact that the few previously reported examples are taxonomically depauperate and from restricted marine environments, has resulted in this event being studied almost exclusively using “shelly” faunas. The main focus of my work is on the exceptionally preserved Fezouata Biota from the Early Ordovician of south-eastern Morocco. This represents the first Early Ordovician Konservat-Lagerstätte from a normal, open marine setting, and hence fills an important gap in our knowledge. Apart from systematic work on this biota, I also am looking into the questions of whether the Cambrian and Ordovician radiations are separate events, or whether the latter is a continuation of the former, and what ecosystem restructuring occurred during the Ordovician. More generally, my main research interests include the taphonomy of exceptionally preserved fossils, metazoan origins and early evolution, and, in particular, arthropod biology.