See also Understanding transformation sorts (ST, GRT), the details for a good run-down on the similarities and differences between the Schwartzian and Guttman Rosler Transformations. A lot of work went into that thread (thanks 5mi11er, merlyn, and others!), and it contains many useful links as well.

HTH,

Update (2005-09-15):

tlm's node above, Re: What is "Schwartzian Transform", contains a broken link to "the famous paper by Guttman and Rosler on sorting in Perl." I have located a copy of the paper here: A Fresh Look at Efficient Perl Sorting, by Uri Guttman and Larry Rosler.

In searching for an online copy of the Guttman-Rosler paper, I found another good resource, authored by John Klassa of the Raleigh Perl Mongers, entitled Sorting in Perl.