Software The following software developed in our lab is availble for use free of charge: FORCIT: Produces first-order reversal curve (FORC) diagrams and related plots. ZPLOTIT: Produces vector demagnetization diagrams, intensity-decay plots, and stereonets and computes the principal component analysis (PCA) from paleomagnetic data sets. The programs are Unix based. You will need some knowledge of compiling and installing software on Unix platforms. All the programs have been tested on Mac PowerPCs or on a MacBook Pro running MacOS X. Please attempt to get the software installed and running on your own before contacting Gary for help, which he will provide only if he has time. As with most freeware, use at your own risk. For bug reports and suggestions for improvement, E-mail Gary Acton at gdacton@ucdavis.edu.