Progress in Model Atmosphere Studies of Wolf-Rayet stars

Recent progress in the quantitative analysis of Wolf-Rayet stars is reviewed, emphasising the role played by choice of spectral diagnostics, clumping and line blanketing on derived stellar properties. The ionizing properties of WR stars are discussed, based on clumped, line blanketed models for WN and WC stars. The role of metallicity and mass-loss is assessed, and the role of HII regions as probes of predicted Lyman continuum distributions. Suggestions are made for differences in observed properties of WCE and WO subtypes.