[jamesbritt]

"... consider reading eigenclass's summary ..."

"Last major update on 2007-10-12"

Casual lurking on ruby-core suggests that all sorts of things have changed since then.

[Locke]

It's still a fairly decent reference if you need to update your software for 1.9. Several incompatibilities I ran into were listed there. For others problems, I did have to search the mailing lists, though.