Cell polarity is fundamental to many aspects of cell and developmental biology and it is implicated in differentiation, proliferation and morphogenesis in both unicellular and multi-cellular organisms. We study the mechanisms that regulate cell polarity during both asymmetric cell division and epithelial cell polarization in Drosophila. To understand these fundamental processes, we are currently using two complementary approaches. Firstly, we are coupling genetic tools to state of the art time-lapse microscopy to genetically dissect the mechanisms of cortical cell polarization and mitotic spindle orientation. Secondly, we are introducing two innovative inter-disciplinary methodologies into the fields of cell and developmental biology: 1) single molecule imaging during asymmetric cell division, to unravel the mechanism of polarized protein distribution within the cell; 2) multi-scale tensor analysis of epithelial tissues to describe and understand how epithelial tissues grow, acquire and maintain their shape and organization during development. Using both conventional and innovative methodologies, our goals over the next four years are to better understand how molecules and protein complexes move and are activated at different locations within the cell and how cell polarization impacts on cell identities and on epithelial tissue growth and morphogenesis. Since the mechanisms underlying cell polarization are conserved throughout evolution, the proposed experiments will improve our understanding of these processes not only in Drosophila, but in all animals.