Ahead of the June 3 trial start date of its price-fixing lawsuit, the Department of Justice is portraying Apple as the “ringmaster” that drew publishers into a scheme to sell digital books on the agency model.

In a memorandum filed in court yesterday, the DOJ ascribes tactics to Apple that ranged from enticing to coercive as it persuaded publishers that it offered their best chance to “challenge the $9.99 price point” set by Amazon.

Five major publishers named as defendants when the lawsuit was filed last year have since settled. According to yesterday’s filing, when the publishers “voiced fears that signing an Apple Agency Agreement would subject them to harsh market conditions unless the other Publisher Defendants signed too, Apple assured the publishers that they would be acting in concert to move the industry.”

Apple spokesman Tom Neumayr, speaking to The New York Times, disputed the government’s claims.

“We helped transform the e-book market with the introduction of the iBookstore in 2010, bringing consumers an expanded selection of e-books and delivering innovative new features,” Mr. Neumayr said. “The market has been thriving and innovating since Apple’s entry, and we look forward to going to trial to defend ourselves and move forward.”

The two sides prepare to battle in court as figures released today underscore just how important the digital market has become to the book industry. According to Bookstats, ebook sales rose by 45 percent in 2012 to make up 20 percent of the market.