Curious about that spooky Masonic temple on 16th Street? Let’s go inside.

“I’ll eat crumbs off of Dan Brown’s table any day,” said S. Brent Morris.

Brent, author of several books on Freemasonry, didn’t mean that literally. He would not actually consume tiny bits of stale bread from the table of the best-selling author of “The Da Vinci Code.”

Rather, it’s a metaphor.

There are a lot of metaphors in the Masons, who are not — most of them, anyway — stonemasons. For example, Brent, 65, is a retired government mathematician who lives in Laurel, Md. He was also my guide on a recent visit to the House of the Temple, the impressive building at 1733 16th St. NW that is the headquarters of the Scottish Rite, Southern Jurisdiction.

But about those crumbs. Besides editing the Scottish Rite magazine, Brent is the author of “The Complete Idiot’s Guide to Freemasonry.” He was inspired to write it after “The Da Vinci Code” came out and the public developed a taste for secret societies. Brent’s book sold 40,000 copies. Then Brown set 2009’s “The Lost Symbol” in Washington, and Brent came out with a new edition and sold a bunch more.

S. Brent Morris, managing editor of Scottish Rite Journal and a 33rd degree Mason, is the author of several books on Freemasonry. (John Kelly/The Washington Post)

“This building is the plot device, the MacGuffin, that the whole novel revolves around,” Brent said.

It is quite a building. It turns 100 this year, so now’s a good time to visit, which even non-Masons can do. And really, haven’t you always been curious about what they do in there?

Well, they don’t drink wine out of a human skull, as in the opening scene of “The Lost Symbol.” That’s the only part of the novel Brent didn’t like. On balance, he thinks, it showed the Masons in a pretty good light.

The headquarters building was designed by John Russell Pope and modeled after the Tomb of King Mausolus, in what is now Turkey. We get the word “mausoleum” from his name.

Pope’s building makes an impression. The roof is a stepped pyramid surmounting an internal dome. Massive stone sphinxes — carved in place by Adolph Alexander Weinman — flank the entrance. Some of the interior’s decorative details are modeled after furnishings found in Pompeii.

“If it was in the Mediterranean, he took it,” Brent said of the region’s influence on Pope.

Although the organization’s staff is located in the building, the coolest part is used only every other year, for the Scottish Rite’s biennial meeting. The centennial gathering kicks off Aug. 22, when about 700 Scottish Rite Masons will descend on Washington. The highest ranking among them will assemble in the soaring Temple Room, with its central marble altar, purple drapes and massive throne for the grand commander.

S. Brent Morris, managing editor of Scottish Rite Journal and a 33rd degree Mason, in the House of the Temple, headquarters of the Scottish Rite, Southern Jurisdiction, in Washington. (John Kelly/The Washington Post)

“It is designed to have a ‘Wow’ effect when you walk in,” Brent said.

On the day I visited, the windows were propped open. The Temple Room does not have air conditioning, but the Masons are in the midst of a $97 million capital campaign that has air conditioning as one of its goals.

Among the building’s other functions, it’s become a repository of member obsessions. There’s a Robert Burns library, because a member collected Burnsiana. There’s a display of pocket watches, because a member liked pocket watches. Ditto walking sticks and penknives.

And there’s a museum devoted to Albert Pike, who rewrote a lot of the Scottish Rite rituals and headed its Supreme Council from 1859 until his death in 1891, and whose remains are buried in the House of the Temple.

Visitors can see Pike’s death mask, his boots, his lead pencil. There’s also a lock of his hair, which raises the interesting possibility that Pike could be cloned and brought back to life.

He probably wouldn’t like what he saw. Pike was a general in the Confederate army and said he’d rather quit being a Mason than allow black members. An African American president 10 blocks down 16th Street probably would have set him off.

I’m still not sure exactly what the Masons do. Brent said they make good men better. They do not, he said, secretly worship Lucifer. It was to rebut such accusations that he wrote his book, along with “Is It True What they Say About Freemasonry?” (with Arturo de Hoyos).

“We don’t really care if you like us or not,” Brent said. “It does bother us if you lie about us.”

I’ll say this about the Freemasons: If they really do secretly run the world, as some believe, they’re doing a pretty poor job of it. I mean, have you seen the world lately?

Brent said Benjamin Franklin (a Mason, natch) put it this way: “The secret of the Freemasons is there is no secret.”

But that’s exactly what you’d expect a secret society to say. What about the super-secret secrets?

“There you go,” Brent said with a chuckle. “I guess, just as they had double secret probation in ‘Animal House,’ the double secrets of the Masons are still tucked away.”

I’m pretty sure he was joking.

Twitter: @johnkelly

The House of the Temple is open to visitors 9 a.m. to 4 p.m., Monday through Thursday. Free admission. Visit www.scottishrite.org.

For previous columns, visit washingtonpost.com/johnkelly.