[en] This paper describes our recent experimental and computational development of short-pulse, enhanced-coherence, and high-brilliance x-ray lasers (XRLs). We will describe the development of an XRL cavity by injecting laser photons back into an amplifying XRL plasma. Using a combination of LASNEX/GLF/SPECTRE-BEAM3 codes, we obtained good agreement with experimental results. We will describe the adaptive spatial filtering technique used to design small-aperture shaped XRLs with near diffraction-limited output. Finally we will discuss issues concerning the development of high-brilliance XRL architecture, with emphasis on scaling the XRL aperture. Combining these advances in XRL architectural components allows us to develop a short-pulse, high-brilliance, coherent XRL suitable for applications in areas such as biological holography, plasma interferometry, and nonlinear optics