Component-Based Problem Solving Environments for Large-Scale Scientific Computing Overview : This paper gives a description of design and implementation of the SCIRun PSE, BioPSE, and Uintah. Fundamental concepts in scientific visualization are covered as well as concepts of object oriented design and practical implementation. Review : The paper gives an excellent explanation of basic problems with the visualization of enormous datasets and the practical limitations associated with design decisions. The daunting task of implementing a practical, parallel, flexible system are explained well. SCIRun is a fairly mature body of software and this paper reflects that fact. Uintah sounds particularly interesting and the focus of a major initiative. From the description in that paper, Unitah is in the design and initial implementation phase. This will certainly be and interesting body of software based on its' genealogy ! Recommendation : Publish as is