Former Treasury secretary Timothy F. Geithner has a new gig and a new assignment.

Soon to be an author. (AP)

The Council on Foreign Relations said Wednesday that Geithner would join as a “distinguished fellow,”  which will give him a perch at the prestigious think tank.

He will also soon meet with publishers as he gets to work on a book and has retained a Washington power lawyer to represent him in post-government activity.

The details of the book have not been worked out, but a source familiar with the project said Geithner wants to write about how to fight global financial crises, as someone who has spent much of his career doing just that. He'd recount the story of the U.S. response to the crisis, which he saw first-hand as president of the Federal Reserve Bank of New York and Treasury secretary.

"We are thrilled to welcome Tim back to the Council on Foreign Relations,” CFR President Richard N. Haass said in a statement. He added, “Both at Treasury and at the New York Federal Reserve, Tim was a tireless, creative and responsible custodian of the public trust.”

Geithner was Obama’s longest-serving senior economic adviser, playing a central role in stemming the financial crisis, lifting the U.S. economy out of recession, overseeing the passage of the Dodd-Frank overhaul of financial regulations, negotiating with Congress over the federal budget and helping support Europe’s efforts to stabilize its financial system.

Many had privately speculated that he would follow one of his mentors, former Treasury secretary Robert Rubin, to Wall Street, but Geithner said that is unlikely. Rubin is a co-chairman of the Council on Foreign Relations.