George Howlett has been using Tcl/Tk to develop software for Electronic Computer-Aided Design (ECAD) since 1990. He also has taught more than a hundred Tcl/Tk courses. George is the author of the BLT Toolkit, a popular extension to Tcl/Tk. His chapter The BLT Toolkit is part of the Tcl/Tk Tools book published by O'Reilly & Associates. George is currently a software engineer at Purdue University, where he develops simulation and visualization software for the Network for Computational Nanotechnology (NCN).