DALLAS (AP) — Charles Martignette’s love of illustration art had largely gone unseen, an incredible collection tucked away in storage rooms and a sprawling warehouse before his death. But as auctioneers prepare for an expected $20 million sale, thousands of pieces of art — from scantily clad pinup girls to wholesome works by Norman Rockwell — will come out of the dust.

Martignette’s roughly 4,300 pieces of art will be up for bidding during a series of auctions at Heritage Auction Galleries in Dallas beginning Wednesday, just more than a year after he died at age 57. Auctions will continue over the next two years with some pieces expected to draw tens of thousands of dollars each.

“He was at the very forefront of collecting this type of material. He was very quirky, very eccentric, but he was also very clever. What he ended up with was the very best examples,” said Edward Jaster, Heritage’s vice president.

Martignette collected art, often oil paintings, that were transformed by printers to illustrate everything from the covers of magazines like the Saturday Evening Post to calendars and paperback books. Much of his collection came from the “golden age” of art illustration, roughly the 1910s through the 1950s.

Among the highest valued pieces is Joseph Christian Leyendecker’s oil painting of a soldier recounting his war story for two children. It became a Saturday Evening Post cover in 1919, and is expected to sell for $50,000 to $70,000.

Gil Elvgren’s 1962 painting of a woman smiling sweetly as she poses on a bearskin rug in a black lace negligee could woo between $30,000 and $40,000. A Dean Cornwell oil painting depicting a sea captain and his crew inspecting a treasure became a Cosmopolitan illustration and could fetch $40,000 to $60,000.

“What Charles hoarded away was the best,” Jaster said. Todd Hignite, consignment director at Heritage, added: “It’s no exaggeration to say this is the most important collection of illustration art ever to be offered.”

Friends paint Martignette — often with the word “character” — as a relentless art hunter, night owl and used clothing aficionado. A photograph from the 1980s shows him in his home, clad in leather pants with a chain around his neck, paintings hanging from floor to ceiling behind him.

Martignette grew up in Massachusetts and moved to Hallandale, Fla., as an adult and began collecting illustration art in the 1970s. Not many others were seeking out the art at the time, but Martignette was relentless in trying to find it.

“He was like a private investigator. He would do genealogy research and track down family members,” said Jim Halperin, co-chairman of Heritage who first met Martignette at a coin show when they were teenagers.

Martignette spent his entire life dealing in art, selling off lesser pieces to finance bigger purchases. Despite the value of his collection, he lived modestly and bought clothes at thrift stores, said friend and business partner Louis K. Meisel.

“He was as cheap as anybody you ever met,” said Meisel, who has an art gallery in New York City and negotiated art deals for Martignette. The pair collaborated on two books: “The Great American Pin-Up” and “Gil Elvgren: All His Glamorous American Pin-Ups.”

Martignette was nocturnal, working from 10 p.m. till 8 a.m. and then sleeping into the afternoon. He filled a 2,500-square foot warehouse in Hallandale with row upon row of art, packing it to the top of the 20-foot high ceiling. He also took over room after room in an art storage warehouse in Miami and packed full two condominium apartments — his own and his parents’ after they died.

“He couldn’t even get to a lot of this stuff,” Meisel said.

Martignette’s focus was illustration art, but his other collections included airplane models, taxidermy and vanity license plates, Meisel said.

Jaster said that in the 2000s, illustration art began selling for record amounts, with Norman Rockwell’s Rosie the Riveter painting sold at Sotheby’s for $4.9 million in 2002.

“Now pinup art is being sought after by people in the pop art realm,” said Jaster, who believes that the genre appeals to a sense of American history, from sexy pinup girls to heroes with guns blazing.

Martignette, who never married and had no children, suffered a heart attack and died Feb. 3, 2008, said Dr. Edgar Phillips, a longtime friend of Martignette and retired pediatrician.

He did not leave a valid will, so his estate went to relatives, who sold it to a group of private investors who consigned the collection to Heritage, according to the auction house.

Phillips said the illustration art that was Martignette’s passion is appealing because it’s “all about life.”

“He enjoyed what he did as much as you can enjoy anything,” Phillips said.