Abstract: Whenever the eqnarray environment appears in a question or example of a problem on comp.text.tex, tex.stackexchange.com or other forums there is a high probability that someone will tell the poster not to use eqnarray. This article will provide some examples of why many of us consider eqnarray to be harmful and why it should not be used.
The article is an updated edition, first published in PracTeX Journal 2006-4.
Lars Madsen holds a master's degree in mathematics from the Department of Mathematics, Aarhus Aarhus, Denmark, where he is also currently employed doing user support including quite a lot of LaTeX editing and general support.
Lars is a regular on comp.text.tex, tex.stackexchange.com plus the Danish TeX User Group's mailing list. As he witnesses a lot of normal LaTeX users, Lars is a bit concerned on how new users learn LaTeX. As a result of this, he is currently (still) working on the third edition of his Danish LaTeX introduction, now spanning almost 500 pages.
He can be contacted at daleif at imf dot au dot dk.