Umbraco newb looking for documentation on using python in macros.

I thought I had found a great resource, but the link is dead: http://umbraco.com/documentation/books/using-ironpython-with-umbraco

Is this documentation available somewhere else? Was it simply taken down because it went out-of-date (bad idea IMHO).

(Also, is it me, or has a wealth of umbraco documentation been lost to dead links?)