Reading a new memoir by former U.S. Defense Secretary Robert Gates, South Koreans may be quite surprised by his characterization of the country's late President Roh Moo-hyun as "a little crazy."

   Gates recalls a November 2007 meeting in Seoul with the liberal-minded president, whose diplomatic and security policy is still being debated.

   He calls Roh "anti-American and probably a little crazy." Roh was quoted as telling Gates that "the biggest security threats in Asia were the United States and Japan."

   The 618-page book, titled "Duty," went on sale Tuesday and has already become sensational for the former secretary's criticism of President Barack Obama for his strategy on Afghanistan.

   Another controversy is expected over such a blunt condemnation of a late foreign head of state.

   In contrast, Gates spoke highly of Roh's conservative successor, Lee Myung-bak.

   "I really liked Lee; he was tough-minded, realistic and very pro-American," he said.

   Gates also revealed some details of when the two Koreas were on the verge of a full-fledged military conflict in November 2010. The North launched a massive artillery attack on the South's western border island of Yeonpyeong.

   He said South Korea's restraint reached its limit as the artillery barrage followed the deadly sinking of a South Korean warship from the North's torpedo attack months earlier.

   "South Korea's original plans for retaliation were, we thought, disproportionately aggressive, involving both aircraft and artillery," he said. "We were worried the exchanges could escalate dangerously."

   Following days of top-level phone conversations with the U.S., South Korea simply returned artillery fire on the location of the North's batteries that started the attacks, he said.

   "There was evidence the Chinese were also weighing in with the North's leaders to wind down the situation," he said.

   Gates served as defense secretary from 2006 to 2011.  (Yonhap News)