Kansas City, Mo. ? The $1.5 million book is tucked inside its own protective case, sitting on a shelf in a huge vault with a steel door 5 inches thick.

It is the rarest and most expensive book the Linda Hall Library of Science has ever bought. Carefully, Bruce Bradley, the library’s curator of rare books, picked up the case and carried it into an adjoining room rich with the dark wood paneling of a grand English library.

He picked up a pair of white cotton gloves, slipped them on and opened the case. Gently, he removed a thin volume weighing a few ounces and placed it on a flat wood table. The book is 464 years old.

“Doesn’t look like such a big deal, does it?” Bradley said.

Except, of course, that it helped change the world.

Published in Latin in 1540, the book is one of the few remaining first editions of the Narratio prima by German mathematician Georg Joachim Rheticus.

Three years before famed astronomer Nicolaus Copernicus published De revolutionibus, the revolutionary treatise stating that the sun, and not the earth, was at the center of the universe, Rheticus published Narratio prima.

In essence, the book of only 70 leaves was “a trial balloon,” said Bill Ashworth, an associate professor of science history at the University of Missouri-Kansas City.

In 1540, Copernicus was 67 years old. At that time, it was scientific and church canon that God’s earth, and thus mankind, occupied the center of the universe. Copernicus had known the real truth for years. The Earth spun on its axis and the planets revolved around the sun. A handful of scientists had urged him to publish his findings.

A rarity

But Copernicus demurred, worried in his old age what would happen if he published the truth. He had all but decided against it until 1539, when the 25-year-old Rheticus visited him and fast became a disciple. He, too, urged Copernicus to publish.

He so believed in the Copernican model, he persuaded Copernicus to allow him, Rheticus, to publish the ideas for the scientific world in his own name to judge the reaction. Rheticus delivered the manuscript to the printers.

Translated, the full title of the Narratio prima, or First Report, is an homage to Copernican thought. It reads: “First Report to Johann Schoner on the Books of the Revolutions of the very learned gentleman and distinguished mathematician, the Reverend Doctor Nicolaus Copernicus of Torun, Canon of Warmia, by a certain youth devoted to mathematics.”

No one is certain how many copies of the original Narratio prima were published, perhaps as many as 300 to 400, with a second printing in 1541.

Today, only about 25 copies are known to exist worldwide. The volume in Kansas City is one of only six in the United States.

“It is one of the rarest and most significant books in the history of science,” Ashworth said. “It really is a treasure. Without it, there may have been no Copernicus.”

Quick approval

That’s because after the publication of the Narratio prima, Copernicus discovered no severe reaction. That came later with Galileo and the Inquisition. In 1543, the same year he died, Copernicus finally published De revolutionibus.

The Linda Hall Library of Science, Engineering and Technology, located at 51st and Cherry streets, maintains a collection of nearly 1 million volumes, including first editions of some of the most significant books in science history. The books are available for public use. They include original editions by Galileo Galilei, Francis Bacon, Robert Hooke, Isaac Newton, Johann Kepler, Copernicus and Darwin’s On the Origin of Species

Although many of the books in the collection are better known than the Narratio prima, they are less rare.

Bradley said the library board has long wanted a copy of the Narratio prima, but only twice in the past 30 years did the library find copies for sale — once in the 1970s and once in the 1980s. Before this purchase, made in November, the most the library spent on a single volume was about $40,000 in the 1980s, Bradley said.

When Bradley found out a copy was for sale through a private owner and dealer for $1.5 million, he notified library president, Lee Jones, who notified the board of the private library.

“I thought it was maybe out of reach for us,” because of the price, Bradley said.

The board decided within minutes and Jones called Bradley.

“He said, ‘Buy the book.’ That was it,” Bradley recalled.

The library officially presented the book to the public at an unveiling and lecture on Thursday. The book’s contents have been digitized and will soon be on the library’s Web site, www.lindahall.org.