CASTA 2009: Workshop on Context-Aware Software Technology and Applications. Co-located with ESEC/FSE 2009, Amsterdam, The Netherlands. Recent developments in dynamic programming languages enable context awareness technically, but the application-oriented communities have had little opportunity to benefit from these insights. Vice versa, certain application requirements concerning context could probably be met better by specially-tailored programming and modeling techniques. This workshop attempts to bring together researchers from the disparate communities to exchange ideas, establish a common research program, and foster new collaborations.