Costume designers occupy a unique position in the creative process: who else knows the intricacies of both the text and of the star’s waist size? The best of them – and Susan Hilferty, who designed the costumes for How To Transcend a Happy Marriage, is one of the best – know a great deal more, as I was eloquently reminded again this past weekend, when I sat down with her in an LCT stage management office as a tech rehearsal took place across the way.

Hilferty has worked once before with playwright Sarah Ruhl and director Rebecca Taichman, on Stage Kiss. “What I love about both of them,” Hilferty said, “is that they bring the designers in very early. I’m part of the process.” She added: “We’ve been working on this play for nine months, and it’s been really thrilling to follow all the threads, literal and figurative, and unravel them.”

Hilferty, who grew up in Arlington, Massachusetts, in a family of six children, has a long history of deep involvement with process. (She is a set designer as well as a costume designer.) “I’ve done 40 productions with Athol Fugard, and with many of them I’ve been a kind of assistant director.” Like LCT’s resident director Bartlett Sher, Hilferty had extensive working histories with the late Garland Wright at the Guthrie and with Des McAnuff at La Jolla Playhouse. She herself tries to be what she counsels her students at NYU/Tisch, where she is chairperson of the Design for Stage and Film department, to be: a theater animal. “A designer,” she said,” “needs to have a comprehensive interest in the whole process as well as a deep commitment to storytelling.”

Some candidates for the NYU program, she related, say that they’re interested in doing pretty dresses and in making people look good. “I tell them that this isn’t the right program for them. Sometimes, a costume designer has to make someone not look good. A character is often in real-life circumstances, and rarely on the red carpet.”

Hilferty, who majored in painting at Syracuse University and has a graduate degree in design from Yale, said that a contemporary play is more challenging to design than a period piece. “Everybody has an opinion about what characters of today should be wearing, because we all live in that world.” She added: “With a period piece, I’m allowed to be the expert.” Contrast in point: in addition to the contemporary world of the Ruhl play, she is designing for the world of 1939 London: Noel Coward’s Present Laughter, which stars Kevin Kline and which opens on Broadway in April.

How To Transcend a Happy Marriage involves a contemporary setting, but the text does not offer specific clues about location. “I think of the two middle-aged couples as living in New Jersey,” Hilferty said, “and the younger characters as living in Bed-Stuy” – a gentrifying Brooklyn neighborhood which has, over the past decade, shed some of its African-American character.

For the Ruhl play, Hilferty began with sketches of the costumes. “You have to start somewhere,” she said, “and you need a road map.” But, she added, “you have to be willing to abandon the map. Once rehearsal begins, and you see how the designs interact with each other and with the actors, you will have to shift something, and that shift has the potential to change everything else.”

A first-rate designer also needs to communicate with a variety of creative types. Hilferty’s career has involved everyone from visionary directors such as the South African Yael Farber -- whose Salome Hilferty designed in 2015: a production that moves later this year to the National Theatre, in London -- to Taylor Swift. “I enjoyed working with Taylor, on her Speak Now World Tour, because she wanted to tell stories onstage, and that’s at the heart of what I’ve always done.”

I have neglected until now to mention Hilferty’s costumes for Wicked: they are a blog entry – a book! – unto themselves. Hilferty imparted fast facts. Among them: the show’s 187 costumes had to be made afresh for each company. Some of the production’s original fabrics became unavailable, so the Wicked organization has had to manufacture fabrics that Hilferty designed. She remained very involved with Wicked for five years after it opened on Broadway, in October, 2003.

Hilferty won a Tony for Wicked, but her philosophy is not dependent on accolades. “I did How To Succeed on Broadway 20 years ago,” she said. “Des McAnuff was the director. When he saw my designs he said, ‘They won’t win any awards, but they’re so smart.’ That’s my epitaph.”

Brendan Lemon is the editor of lemonwade.com