U.S. Treasury Secretary Jack Lew's interview this week about lobbying Chinese leaders to reverse course on devaluing Chinese currency serves as a reminder that currency squabbles between countries continue.

Lew, for his part, wants China to keep moving further towards the direction of a market-based exchange rate. "If they want the renminbi to be a world currency some day, if they want it to be a reserve currency some day, they need to demonstrate that," Lew told CNBC Wednesday.

"From our perspective, it is something that is very important in preserving a level playing field for trade in the world."

The China-U.S. currency dynamic is just one issue James Rickards, author of the bestselling book Currency Wars, revisits and pushes forward in his new book, "Death of Money: The Coming Collapse of the International Monetary System".

Currency Wars detailed a Pentagon-sponsored excercise Rickards took part in back in 2009 -- the Pentagon's first-ever financial war game -- where players could not use actual, physical weapons like bombs, but could only use financial weapons like stocks, bonds and derivatives to destroy the enemy.

Related: Tensions between Russia and U.S. heat up again: Which country has more to lose?

Rickards played on the China team, which created a scenario where Russia and China combined forces, and used their gold to issue new, gold-backed currency and turn their back on the dollar.

Related: Don't write off gold just yet: Jim Rickards

"We were actually laughed at by some of the Harvard types at the time," he tells us in the video above. "But since then...things are actually playing out the way we told the Pentagon in 2009."

He cites Russia increasing their gold reserves by 70% and China increasing their gold reserves by several hundred percent since that time as evidence.

But as Jack Lew pointed out just this week, China is still a long way away from becoming a reserve currency given other issues with the convertability of the renminbi.

Rickards concedes that China is not there yet, but says there are a lot of things going on, a number of "important straws in the wind that weaken the dollar at the margin."

Check out the video to see why Saudi Arabia could pull the rug out from under the dollar, according to Rickards.

Also, we ask, why this book now? The U.S. dollar has been strengthening, and central banks in the U.S. and Europe aren't worried about inflation (the type that pundits have warned could erode confidence in a currency like the dollar), they are concerned about the lack of inflation or even the threat of deflation. Rickards response? Watch the video to find out.