Three separate versions of a secretive Federal Reserve Bank of New York manual known as the “Doomsday Book” were entered into court evidence under seal Tuesday as part of a classaction lawsuit by shareholders of American International Group Inc.

The “Doomsday Book” is essentially a private compilation of emergency measures that the Federal Reserve could take in the event of a financial crisis or other market-destabilizing event. The book has never been made public.

It’s existence of the book isn’t secret: Treasury Secretary Timothy Geithner references it in his recent financial-crisis book, “Stress Test,” calling it a catalog of “our actual firefighting equipment.”