For more than 50 years, research on ceramics has a focus on processing with polymeric precursors. These so-called preceramic polymers consist of an inorganic silicon-containing backbone and organic side groups, which allow for plastic shaping prior to thermal treatment for polymer-to-ceramic transformation, in this paper addressed as pyrolysis, typically under exclusion of air. Due to a massive density change during pyrolysis shrinkage may amount up to 80 vol. %; (partial) compensation can be achieved by addition of particulate fillers. The combination of the preceramic polymer, the fillers, pyrolysis atmosphere and pyrolysis temperature spans a wide parameter field which allow for a tailor-made microstructure with a multitude of materials functionalities in ceramic processing.