Life is made up of moments, and so is Arthur Laurents’ 1959 Broadway musical, “Gypsy,” with lyrics by Stephen Sondheim and music by Jule Styne. Regarded as the great American musical by many critics, “Gypsy” is based on the memoirs of the renowned, high-class stripper named Gypsy Rose Lee. It recounts the challenges of growing up Louise in the shadow of her sister, billed on the vaudeville circuit as Dainty June. June is blond and petite (and later became actress June Havoc) and considered the more talented daughter by Mama Rose, who relentlessly trained them to become the stars she knew they were.

Along the road, Mama picks up a sweet, live-in manager named Herbie, as well as a cow and several other youngsters, who become the back-up group for Dainty June and Louise. Despite the fact that Mama Rose pretends they are pre-teens, June and Louise grow up. When June leaves to become part of a dance act with a boy named Tulsa, Mama focuses all her attention on Louise, who becomes Gypsy Rose Lee when she is thrust onstage to strip when the vaudeville and the act reach their nadir. The hard-edged Mama Rose, who refuses to marry Herbie, loses him and Gypsy, too, abandons her.

Life’s moments can be large or small, momentous or forgettable. When he wrote “Gypsy,” Laurents chose moments of memoir large and small focusing on them to tell this tale of a performer, the end of an era, and the art form that chose her and which she imbued with elegance and class.

Ion Theatre’s production of “Gypsy” (playing through Nov. 27 at BlkBox@6th at Penn) may lack size but it doesn’t lack in emotional scope and impact, and the latter is even more enhanced by the proximity of the performers. And it’s all there – tears and tap dances.

Louise/Gypsy is played by excellent young singer/dancer Katie Whalley, who was raised in Vista and was seen recently as Fritzie in Cygnet’s Cabaret. She manages Louise’s hangdog insecurity and almost grows into Gypsy’s eventual devil take the hindmost.

June is played by Helena Marie Woods, a seasoned 17-year-old singer/dancer who also lives in San Diego. Woods captures June’s demands without being annoyingly cloying and ditzy, sublimating her own extraordinary competence to appear incompetent. Credit for both these performances must rest with the young women and to co-directors Claudio Raygoza and Kim Strassburger.

There’s no “Gypsy” without Mama Rose and ion has the perfect Rose in actor singer Linda Libby, a Craig Noel award winner for her solo turn in ion’s 2008 “Request Programme,” and as Frau Schneider in Cygnet’s recent Cabaret. She sells “Everything’s Coming Up Roses” and breaks one’s heart in “Rose’s Turn.”

Herbie brings out whatever softness lives inside Rose and the role is beautifully played here by the endearing dancer/singer Andy Collins, one of the city’s under-sung talents. Additional company members Gracie Lee Brown, Jordan Bunshaft, Gigi Coddington, Betsy Dunbar, Emily Gordon, Eric Hellmers, Ralph Johnson, and Justin Warren Martin and Ben Shaffer excel at every role they’re given, including impresarios, lechers, dignified Frenchmen, strippers and the back end of a cow.

The proceedings are considerably enhanced by the excellent piano of Wendy Thompson, choreography of Ali Whitman, lighting by Karen Filijan, costumes by Joan Hanselman-Wong, scenic/sound/ projections by Raygoza and scenic construction by Matt Scott.

San Diego musical theater aficionados are urged to see this small, brave production of a piece of classic American theater.