My research encompasses palaeontology (from systematics and phylogeny to palaeoecology), palaeobiogeography, palaeogeography, stratigraphy and sedimentary geochemistry. Much of my effort is being directed to interpretation of the history of life and its fossil record in the Cambrian and Ordovician, and the related issue of high-resolution of geologic time through these periods using multiple chronostratigraphic methods. Altogether, this has enabled me to address a wide spectrum of palaeobiological and geological problems and has resulted in well over 130 published papers and books.

Currently, I am involved in several topically and geographically wide-ranging projects. These fall under five broad themes: (1) The Ordovician deep-water shelf successions of Baltica – stratigraphy, faunal turnovers and palaeoenvironmental changes. Principal collaborators: Stig M. Bergström (Columbus, Ohio, USA), Mikael Calner (Lund, Sweden), Mats E. Eriksson (Lund, Sweden), Sven Egenhoff (Fort Collins, Colorado, USA), David A.T. Harper (Durham, England), Michael M. Joachimiski (Erlangen, Germany), Frans Lundberg (Lund, Sweden), Jörg Maletz (Berlin, Germany) and Seth A. Young (Tallahassee, Florida, USA); (2) Cambrian chronostratigraphy and intercontinental correlation. Principal collaborators: Loren E. Babcock (Columbus, Ohio, USA), Gerd Geyer (Würzburg, Germany), Arne T. Nielsen (Copenhagen, Denmark) and Shanchi Peng (Nanjing, China); (3) Cambrian palaeogeography and palaeobiogeography. Collaborators: J. Javier Álvaro (Madrid, Spain), Loren E. Babcock (Columbus, Ohio, USA) and Anna Zylińska (Warsaw, Poland); (4) Trilobite palaeobiology – functional morphology, life habits, ontogeny, and evolution. Principal collaborators: Loren E. Babcock (Columbus, Ohio, USA), Peter Cederström (Eslöv, Sweden), Euan N.K. Clarkson (Edinburgh, UK), Mats E. Eriksson (Lund, Sweden), Gerd Geyer (Würzburg, Germany), Lukáš Laibl (Prague, Czech Republic) and Brigitte Schoenemann (Cologne, Germany); (5) The Alum Shale Formation of Scandinavia – stratigraphy, faunas and depositional environment. Principal collaborators: Loren E. Babcock (Columbus, Ohio, USA), Euan N.K. Clarkson (Edinburgh, UK), Sven Egenhoff (Fort Collins, Colorado, USA), Mats E. Eriksson (Lund, Sweden), David A.T. Harper (Durham, England), Arne T. Nielsen (Copenhagen, Denmark), Timothy P. Topper (Stockholm, Sweden) and Anna Zylińska (Warsaw, Poland).

Since August 2020, I am Chair of the International Subcommission on Cambrian Stratigraphy (ISCS). The primary objectives of the ISCS are to define the series and stages of the Cambrian by means of the internationally agreed rules of the International Commission of Stratigraphy (ICS) and to provide the international forum for scientific discussions and interchange on all aspects of the Cambrian.