Michael McLennan received a Ph.D. in 1990 from Purdue University for his dissertation on dissipative quantum mechanical electron transport in semiconductor heterostructure devices. He became a Tcl enthusiast when he joined Bell Labs in 1992 to work on tools for semiconductor device and process simulation. He is co-author of “Effective Tcl/Tk Programming” (published by Addison-Wesley) and “Tcl/Tk Tools” (published by O’Reilly and Associates). He also developed Tcl, an object-oriented extension of Tcl, which is now used by thousands of developers worldwide, on projects ranging from the TiVo digital video recorder to the Mars Pathfinder. Dr. McLennan was an Architect at Cadence Design Systems, where he developed the SimVision visualization and debugging environment for NC-Sim. He is currently a Senior Research Scientist at Purdue University, where he develops simulation and visualization software for the Network for Computational Nanotechnology (NCN). His latest project is the Rappture toolkit.