Researchers from 11 Sections/ Laboratories/ Branches have used the Facility during the past year. Publications resulting from this work are listed in the bibliography. Several manuscripts have been submitted recently and are not listed. Microscopy done in LIS in the past year has contributed to expand knowledge in each of the NIAMS research areas: i) understanding the immune system and its diseases (Casellas et al, 2009); ii) understanding bone and cartilage, their multipotent cells and possible modes of repair, as well as bioengineering of replacement tissues (Colburn et al, 2009;Gagarina et al, 2010;Pricola et al, 2009); iii) understanding skin development (Duverger &Morasso, 2009); iv) understanding basic cardiac (Manisastry et al, 2009) and skeletal (Zhang et al, 2009) muscle biologies; v) understanding muscle diseases such as Pompe Disease (Raben et al., 2009 &2010;Takikita et al, 2009;Xu et al, 2010) and Duchenne Muscular Dystrophy (Prins et al, 2009). The reach of the microscopy techniques available to NIAMS researchers has been expanded by several additions: a laser capture and microdissection instrument has been upgraded and moved to the Facility;several software and hardware improvements have been made to the Total Internal Reflection Fluorescence (TIRF) microscopy system;and thanks to ARRA funds we have added a single molecule detection platform for Fluorescence Lifetime Imaging Microscopy (FLIM). Finally, one of our confocal microscopes has been fitted with an objective inverter, new objective and external stage for 2-photon intravital microscopy.