Acknowledgements

These days most non-trivial software packages have evolved over a long period of time and PLT is no exception.

The first program to bear the name of QDP was written in the late 1970's by Andy Szymkowiak for use by the X-ray group on a PDP 11/70 at Goddard Space Flight Center. Although I don't think that a single line of code has survived from that original version, I am grateful to Andy for that version, and hence for the basic idea of an interactive graphics program.

The QDP/PLT development flourished during my years at the Institute of Astronomy, Cambridge, U.K. I am grateful to Andy Fabian for being able to fund my stay there, and also for providing the stimulating environment where such working software could be developed. It is important that PLT was developed not as a software project, but rather to meet real needs in the analysis of data.

Now that I am at Marshall Space Flight Center, I would like to thank Martin Weisskopf for his continuing support of these efforts.

I am grateful to Tim Pearson for providing and for continuing to support the PGPLOT graphics package. PGPLOT is flexible, easy to use, portable and device independent.

Numerous other people have made contributions to PLT, ranging from simple comments, such as ``it doesn't work when I do this", to actually providing the code for new features. Some of these people are mentioned in the on-line help file under the ``history" subtopic. I would like to say thank you to all the people who have offered comments.