According to Wikipedia:

Perl was originally named "Pearl", after "the pearl of great price" of Matthew 13:46. Larry Wall wanted to give the language a short name with positive connotations; he claims that he looked at (and rejected) every three- and four-letter word in the dictionary. He also considered naming it after his wife Gloria. Wall discovered before the language's official release that there was already a programming language named PEARL and changed the spelling of the name.

note: Schwartz and Christiansen? Apparently, you have the same edition of Learning Perl that rests on my shelf. I can't swear to it, having never laid eyes on a first edition, but I'm pretty sure it originally only bore Randal Schwartz's name (I suppose I should ask him next time I correspond with him). The second edition (which is what I own) also bears Christiansen's name, and the words "UNIX programming" grace its cover near the top. The third edition is credited to Schwartz and Tom Phoenix (the same credit on Learning Perl Objects, References, and Modules, also an excellent book that has in its second edition come to be called Intermediate Perl): the third edition has had a significant bit of its unixy bias cut from it. The fourth edition is credited to "Randal L. Schwartz, Tom Phoenix, and brian d foy", with the latter being a well-known member of the PerlMonks community. According to brian d foy, the last vestiges of platform-specific bias were removed from the text of the book and some rearrangement was done.

Err, that was a bit more than I initially intended to say. I just happened to notice that you credited the authors listed on the second edition, which is the same edition I have on my shelf. I've read parts of the fourth edition, however. There are definitely parts of the second edition I prefer, but since I've been doing basically all of my Perl work with unices in mind as the platform, the platform-agnostic approach of the fourth edition isn't terribly important to me.