Let’s all party like it’s 1962!

The new Book-It Repertory Theatre dramatization of Olympia author Jim Lynch’s novel “Truth Like the Sun” kicks off with an ecstatic bash on the eve of the ’62 World’s Fair in Seattle.

Civic movers and shakers in gem-colored tuxes, and women in bouffant hair and cocktail wear do the twist and toast Champagne and marvel at their surroundings — the rotating restaurant atop the spanking-new Space Needle.

They cheer on a vision of Seattle as a metropolis of the future, forging ahead into modernity, and ready to be taken seriously by those pacesetters on the opposite coast — who basically dismiss this burg as an outpost of lumberjacks.

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In his spirited and vigorous novel, Lynch invented a symbolic figure to represent that maverick civic drive attached to the fair, and to embody modern Seattle itself. He is Roger Morgan (played for Book-It by an agreeable, energetic if only mildly magnetic Chris Ensweiler).

Roger is the “grand exalted dreamer” and glad-hander who in this fictitious account pretty much runs the 1962 shebang, and gets the whole town behind it. (In actuality, it was a group of men leading the charge.)

As the adapter of this atmospheric story for Book-It, Kevin McKeon (who also ably portrays Morgan’s longtime sidekick and fixer, Teddy) had his work cut out for him.

For one thing, the narrative of “Truth Like the Sun” seesaws between 1962 and 2001, when Morgan’s surprise run for mayor ignites an investigation by an enterprising young journalist, Helen (Jennifer Lee Taylor).

The back-and-forth pacing between the two eras is choppy, despite the entertaining way director Jane Jones covers the costume and era changes with Nathan Wade’s zingy sound design and hot pastel spotlights (courtesy of lighting designer Marnie Cummings).

A greater challenge: turning the book’s significant amount of exposition and vivid description into dialogue — a transformation Book-It often masters with flair, but is only partly successful with here. (One example: remarks from VIPs who visit the fair — Elvis, LBJ — are awkwardly mimicked by Roger, instead of quoted directly.)

Local ambience and fun familiar references do saturate the production.

The tension between newcomer Helen’s impressions of Seattle (which she finds smug and provincial, then appreciates) and Roger’s fervent boosterism is communicated well. So is Lynch’s balanced advocacy for both the Fourth Estate’s role in uncovering murky civic affairs, and for go-go urban mavericks who can realize a city’s potential.

The shady real estate dealings that Helen digs out of Roger’s past are convoluted and sometimes confusing in this retelling. And the stop-and-go signals she gets from her editors at the old Seattle Post-Intelligencer are conveyed in a newsroom milieu that retains musty “stop-the-presses!” clichés.

But neither Lynch’s novel, nor Book-It’s treatment of it, settles for easy heroism or villainy. McKeon’s irascible Teddy and Taylor’s dogged Helen are believably flawed and admirable. And Roger isn’t simply defined by his gumption and can-do charisma, nor by some slippery deals and his botched romances with a bubbly fiancé (Laura Hanson) and a worldly married lover (Leslie Wisdom).

There’s a bit of the enigmatic Jay Gatsby in Roger, and more than a pinch of “Mad Men’s” Don Draper. All these male characters are American success stories, who reinvented themselves from the ashes of troubled pasts.

Ensweiler’s Roger does not project a golden boy aura of suavity, which Book-It’s “Truth Like the Sun” could have used. But he does exude the ambitious optimism of a basically decent man who dreams big, and acts on those dreams.