In his new book, “The Upper House: A Journey Behind the Closed Doors of the U.S. Senate,” longtime Washington journalist Terence Samuel threads a neat needle. He sympathizes with dynamic, fresh-faced Senators who arrive in the storied body in 2007 hoping to change the world, only to find that the wheels of the institution grind slowly, if at all.

Yet Samuel also maintains that the Senate’s low metabolic rate is a virtue. “To many observers, it looks like a lot of wasted time, but the horse trading and deal making were woven into the institution to guard against whimsical lawmaking,” he writes. In other words, Samuel celebrates the “cooling saucer” role designed for the Senate by the Founding Fathers, and at the same time recognizes how outdated that implement might look on the modern dining table of politics.

Samuel focuses his story of the chamber not on its longtime stalwarts or its senior Members — who had already learned their way around the Senate’s curious landscape — but on the freshman class of 2007, and the least stereotypically “Senatorial” Members at that.

There’s Sen. Amy Klobuchar, the blunt and funny Minnesota Democrat balancing being a mother and a public servant. Sen. Jon Tester, the Democratic Montana “farmer with the flattop and … three missing fingers.” Virginia Democratic Sen. Jim Webb, the renaissance man of the Senate whose résumé includes dodging fire as a Marine Corps officer in Vietnam and publishing novels. Sen. Bob Corker, the Tennessee Republican, is the most central casting Senator of the bunch, with his “Type A” personality and expensive suits. But his position as a Republican in a largely Democratic class makes him an interesting case study.

Through the eyes of these Senate newcomers, the traditions of the “upper chamber” appear both maddening and necessary.

Samuel wisely gears his book more to the interested citizen than to the die-hard political junkie. His writing reveals little of the back-room deal-cutting and sniping that fascinates inside-the-Beltway readers. Rather, he explores the traditions and evolutions that make the Senate such a fascinating beast. “It is the curse of a modern senator that if you get sent to Washington, you have to make sure everyone back home understands you are not ‘of Washington,”‘ he writes while describing Klobuchar’s peripatetic life, shuttling between her family in Washington and her constituents in Minnesota.

To better appeal to his audience, Samuel distills the notoriously difficult-to-explain filibuster in a few concise lines and offers a few brief history lessons and a CliffsNotes distillation of the seminal-but-wonky writings of Norman Ornstein (a Roll Call contributing writer) and Thomas Mann. That is not to say that he reduces the chamber to “Schoolhouse Rock” simplicity.

In fact, he rejects glib explanations of the Senate’s reputed loss of decorum (“too many former House members,” one Senator postulates), noting that it was two former House Members — Sen. Tom Daschle (D-S.D.) and Trent Lott (R-Miss.) — who led their respective parties with institutional respect and comity.

Samuel also humanizes Senators too often seen in partisan caricatures or vitriolic cable news clips. Senate Majority Leader Harry Reid (D-Nev.) talks about his love for Hollywood movies and Woodie Guthrie songs. Sen. Robert Byrd (D-W.Va.) reads a poem on the Senate floor. Tester, Webb and Sen. Claire McCaskill (D-Mo.) jokingly form the “Redneck caucus.” Senators kiss and laugh and fret.

The book focuses on the dynamic period from the 2006 elections up to the health care vote this year: the public revolt against the Iraq War, the swearing-in of President Barack Obama and the ascendency of Nancy Pelosi (D-Calif.) to Speaker. Many of that era’s circus-like moments show up, too, and its earlier years in particular recall a GOP in free-fall. There’s former Sen. George Allen’s (R-Va.) “macaca” gaffe, former Sen. Conrad Burns (R-Mont.) using the N-word in a joke, and former Senate Majority Leader Bill Frist (R-Tenn.) diagnosing coma patient Terri Schiavo via videotape.

Samuel does not offer the meaty meal that is, say, Robert Caro’s landmark “Master of the Senate,” a definitive portrait of the body. But a more casual reader will find Samuel’s Senate filled with real people and their problems that don’t seem so grand as to deserve the highfalutin moniker of “the upper chamber.” And that’s not such a bad thing.