Indiana University-Purdue University Indianapolis (IUPUI) / Reproducible computing and research are of great importance for scientific investigation in any discipline. This thesis presents a general approach to provenance in the context of workflows for widely used script languages. Our solution is based on system integration, and is demonstrated by integrating MATLAB with VisTrails, an open source scientific workflow system. The integrated VisTrails-MATLAB system supports reproducible computing with truly prospective and retrospective provenance at multiple granularity levels as scientists choose for their scripts, and at the same time, is very easy to use.