“I’m stunned, exhausted, and thrilled,” the auctioneer for Christie’s, Christopher Burge, said summing up the spring auction season. The rest of the art world shares the sentiment.

In a 10-day trading frenzy, buyers spent $1.49 billion on art. Although there were significant and impressive sales in the Impressionist and Modern category, the heat in the market continues to be in contemporary art, which accounted for $870 million in sales, with 121 works selling for $1 million or more.

These startling numbers confirm what the art world has known for some time: A sea change has taken place. Contemporary art has the lion’s share of dollar volume. This has been true for a few seasons now, but now contemporary also has the overvalued masterworks. Perhaps that’s why collectors who previously bought Impressionists are moving into the contemporary category with confidence and plenty of cash. That is where the trophies lie, and collectors are voting with their feet.

“Five years ago, the sale totaled $60 million,” the director of Christie’s Post-War and Contemporary Art, Brett Gorvy, said. This year, Christie’s day sale — where the less expensive and less significant works are sold — totaled $93 million alone. The entire category pulled in just shy of half a billion dollars for the auction house and required four senior specialists to assemble. A major sale is usually the work of one or two department heads.

The change hasn’t come without skepticism and even dismay. The fact that an Andy Warhol painting could sell at the same level as a Mark Rothko will take some getting used to for many art lovers. The fact that some of the first major contemporary art collections are coming of age should help change that prejudice. Scarcity and provenance sell pictures. Great collections raise the stature of the paintings held within. And now many of the Pop art and contemporary collectors are reaching an age where they want to realize the value of their collections rather than burdening their heirs with the job of disbursing the art. The validation of high prices can’t hurt either. Several of the most spectacular sales in Warhol, Jasper Johns, and Rothko were for works that had been held for several decades or seen but one farsighted owner.

Buyers covet paintings with such a secure provenance. But the larger constituency of those who appreciate art have not seen or necessarily valued these works. The auction houses are aggressively educating buyers in the contemporary category. They are producing more single-painting catalogues. In the case of Warhol’s “Green Car Crash” (1963), Christie’s took the unusual step of creating a video of an interview with Gerard Malanga, the assistant to Warhol who helped create it and many other works.

One reason for the effort to educate is the potential gain in new collectors. The contemporary market has been flooded with new buyers at every price point. With Phillips solidifying its position at the forward edge of the market, there is now an auction for every buyer. Billionaires battled over the big works in the evening sales, but the daytime bidding was just as fierce, though at a lower price level. At Phillips, there were many of the same dealers one sees at the evening sales — including Larry Gagosian — but a host of faces who probably would not qualify for a ticket to the marquee evening sales uptown. No matter. Several, buying for themselves, were happy to throw in a million-dollar bid when the time came.

The change in the market has also changed the styles of the auctioneers. Simone de Pury is a most restrained Swiss in person. When Phillips ran its sales from its 57th Street location, he was the model of the cool, commanding auctioneer. But in the loud and boisterous salesroom Phillips now uses downtown in the meatpacking district, Mr. de Pury is animated and aggressive. Last Thursday night, he dipped down in the pulpit like an evangelist. “Say 750. Just say it!” Mr. de Pury said. “Make the last effort — make it!”