James Comey has sold 600,000 copies of his hotly anticipated memoir A Higher Loyalty: Truth, Lies and Leadership in its first week.

The former FBI director has outsold Hillary Clinton's What Happened at a ratio of 3:1 already.

Comey signed a $2million deal for the memoir with Flatiron after being fired by President Trump in 2017.

Details of the contract, specifically how much more he will earn if sales skyrocket, remain unclear.

Since before the book was available on April 17, he has been promoting it enthusiastically on television stations across the country.

James Comey's memori, A Higher Loyalty: Truth, Lies and Leadership, has sold 600,000 copies since it was published on April 17

Clinton's book sold 300,000 in its first week after being published last September.

It went back to print three times in its first week, putting 800,000 in circulation.

By contrast, Comey's memoir has been printed 1 million times.

Comey has also outsold Fire and Fury by Michael Wolff which sold around 300,000 in its first week

He has also outsold Michael Wolf's explosive Fire And Fury which

He has however drawn criticism for the timing of its publication given the ongoing probe into Russian interference in the election.

Earlier this week, Senator Susan Collins said he was 'cashing in' on the timing and potentially jeopardizing the result of the Special Counsel investigation as a result.

'I cannot imagine why an FBI director would seek to essentially cash in on a book when the investigation is very much alive,' she said.

President Trump has also slammed the book and cited an ongoing investigation by the Department of Justice's internal watchdog into whether Comey leaked classified information by sharing details of memos he took from meetings with the president.

Comey has always maintained that he did not leak any classified information.