Even a cursory glance at the recent paleontological literature should convince anyone that quantitative methods in paleontology have arrived at last. Nevertheless, many paleontologists still hesitate in applying such methods to their own data. One of the reasons for this has been the difficulty in acquiring and using appropriate data-analysis software. The 'PALSTAT' program was developed in the 1980s in order to minimize such obstacles and provide students with a coherent, easy-to-use package that supported a wide range of algorithms while allowing hands-on experience with quantitative methods. The first PALSTAT version was programmed for the BBC microcomputer (Harper and Ryan 1987), while later revisions were made for the PC (Ryan et al. 1995). Incorporating univariate and multivariate statistics and other plotting and analytical functions specific to paleontology and ecology, PALSTAT gained a wide user base among both paleontologists and biologists.

After some years of service, however, it was becoming clear that PALSTAT had to undergo major revision. The DOS-based user interface and an architecture designed for computers with miniscule memories (by modern standards) was becoming an obstacle for most users. Also, the field of quantitative paleontology has changed and expanded considerably in the last 15 years, requiring the implementation of many new algorithms. Therefore, in 1999 we decided to redesign the program totally, keeping the general concept but without concern for the original source code. The new program, called PAST (PAleontological STatistics) takes full advantage of the Windows operating system, with a modern, spreadsheet-based, user interface and extensive graphics. Most PAST algorithms produce graphical output automatically, and the high-quality figures can be printed or pasted into other programs. The functionality has been extended substantially with inclusion of important algorithms in the standard PAST toolbox. Functions found in PAST that were not available in PALSTAT include (but are not limited to) parsimony analysis with cladogram plotting, detrended correspondence analysis, principal coordinates analysis, time-series analysis (spectral and autocorrelation), geometrical analysis (point distribution and Fourier shape analysis), rarefaction, modelling by nonlinear functions (e.g., logistic curve, sum-of-sines) and quantitative biostratigraphy using the unitary associations method. We believe that the functions we have implemented reflect the present practice of paleontological data analysis, with the exception of some functionality that we hope to include in future versions (e.g., morphometric analysis with landmark data and more methods for the validation and correction of diversity curves).

One of the main ideas behind PAST is to include many functions in a single program package while providing for a consistent user interface. This minimizes time spent on searching for, buying, and learning a new program each time a new method is approached. Similar projects are being undertaken in other fields (e,g., systematics and morphometry). One example is Wayne Maddison's 'Mesquite' package.