Nancy Sinatra is one of the most fluid superstars of the last fifty years. As a singer, movie starlet, multimedia trendsetter, proto-feminist muse, and fashionista, Sinatra has maintained an undeniable presence in contemporary culture. Through a series of mythic collaborations with Lee Hazlewood, Mel Tillis, Elvis Presley, Bobby Darin, Morrissey, and her famous father, she popularized the form of the male-female duet in American rock and roll. Her susurrating vocal style, sourced and echoed a hundred times over by the likes of Kim Gordon, Britta Phillips, and Lana Del Rey, divined the best elements of European chansons, jazz-blues, and confectionary standards with a loping, almost sardonic drawl that belies her New Jersey birthright. Heard in baroque masterpieces like “How Does that Grab You, Darlin’?” and “Summer Wine,” this vocal persona (whose apocryphal description as a “fourteen-year-old who screws truck drivers” is attributed to Hazlewood) caused the producer to refer to her by the affectionate moniker “Nasty.” Her bleached bouffant and leather boots introduced a particularly Californian “go-go” aesthetic from Europe, immortalized in the Movin’ with Nancy TV specials and her omnipresent classic “These Boots Are Made for Walkin’.”

Nancy Sinatra’s career mirrors that of countless female artists who have come before and after her; namely, the fact that its prescience and influence have often been diminished (by both men and other women) because of her gender, and that its great successes are sometimes yoked unfairly to the men who surrounded her.

Ten years after her self-titled “comeback” album, and two decades since she last mounted a reunion tour with Hazlewood (who passed away, of cancer, in 2007), Sinatra continues to work in publishing, film, and music, and has produced two albums of unreleased material on her own Boots label: Cherry Smiles: The Rare Singles (2011) and Shifting Gears (2013). Just as their titles promise, Cherry Smiles is a fabulous collection of Nancy rarities from the vaults, while Shifting Gears, also dated from the early ’70s but painstakingly re-recorded and remastered, offers a parallax view of Nancy—neither the proto-punk cowgirl of the counterculture nor the reinvented indie-rock chanteuse of Nancy Sinatra (2004)—with stringladen renditions of Rodgers and Hammerstein, Jimmy Webb, and George Gershwin revealing just how incandescent and timeless her simpering voice is when wedded to the Great American Songbook.

As the fiftieth anniversary of “These Boots Were Made for Walking’” approaches, and rock and roll enters a seventh, geriatric decade, I spoke by telephone to one of its grand dames. Sinatra was a forthright and commanding conversationalist. She remains aware of her celebrated pedigree in popular music, and spoke of her aural and visual contributions to the medium, her second thoughts on the past, and her plans...