There is an enhanced reproduction of the original Action manual in PDF form but it's in German language.
The tables and examples are still useful to English speaking people.
I wish I knew how to extract text from a PDF so I could run a translator on it. I have the Action manual (English) in print form but it is poorly written and not indexed. A computer version would be helpful, for searching.
Something to get you started is Clinton Parker's Action tutorial, published in Analog Computing. Clinton Parker is the Author of the Action language (well, I think he is).
You'll find plenty more good information at Carsten Strotmann's site.
Steve Sheppard
p.s. I'm no expert on Action but if you have any questions I'll try to help. You can reach me at Stephen S*h*e*p pard dot COM (remove all the spaces and *'s).