These books are part of the J installation online help.
If you are new to J and want to be a J programmer, reading the Primer is a good place to start. Even if you have considerable programming experience, there is much that is unique to J, and it is worthwhile to at least skim this book before jumping into the deep end.
The Dictionary is the authoritative and definitive specification of the J language. It can be used to learn J, but the fact that it covers all of the language concisely, yet completely and rigorously, with more emphasis on the complex than the mundane, means that most beginners should start with the introductory books.
Roger K W Hui, Kenneth E Iverson - Copyright Jsoftware
A Russian translation is available. See Konstantin Metlov's note on the Links page.
The User Manual documents the J programming environment, standard library and various other topics such as DLL calls and ODBC.
Lists the changes in progress for the next beta: J806.
Lists the changes in the current distribution: J805.
Lists the changes in the previous distribution: J804.