We report on progress in developing thick silicon detectors for X‐ray and gamma‐ray astronomy. Silicon detectors offer good spectroscopy at reasonably low cost and with low internal background in the energy range between 5–50 keV. This technology offers a smooth energy response and a very fast timing response for high rate applications. We are testing large area, double‐sided 2mm thick detectors for applications requiring large quantities of silicon. Our current laboratory prototypes are 63 × 63 mm in area, and we will soon have detectors that are 95×95 mm in area and with thicknesses up to 3 mm. As part of our prototyping efforts, we are developing double‐sided strip detectors, pixel detectors, as well as hybrid pixel/strip detectors. We present our latest laboratory results in terms of imaging and spectroscopy, as well as our progress in developing and integrating custom readout ASICs. These detectors and electronics, while not a perfect match for a next generation X‐ray timing mission, form a good basis for the design of dedicated large area detectors in the 5–50 keV energy range. © 2004 American Institute of Physics