The program DCDT+ is a Windows implementation of Walter Stafford's DCDT algorithm integrated with non-linear curve fitting to derive sedimentation and diffusion coefficients (or molecular mass) for up to 5 components in a mixture, using a user interface similar to that in SVEDBERG. It comes with context-sensitive Help, tutorials, and "how-to" guides. A complete program description may be found at http://www.jphilo.mailway.com The program itself may be downloaded for a 30-day free trial from that site.