When Alfred Charles Kinsey was hired as an assistant professor of zoology at Indiana University in 1920, he began a two-decade study of the gall wasp, collecting over 1 million samples. He loved the gall wasp, he said, because each one was totally different from the others. In 1938, at the behest of curious students, he taught a course called “Marriage” that was designed to dispel the sexual myths that were confounding and frustrating young people. (“Is it true that oral sex can cause problems getting pregnant? Will excessive masturbation lead to impotence?”)

Kinsey gave the students what they wanted, and then some. Soon his students were taking a written questionnaire about their sex lives. Then he designed a 350-question interview process, and within two years Kinsey and colleagues were traveling across the country conducting thousands of interviews. They discovered that when it came to sex, each subject was totally different from the others.

Kinsey, written and directed by Bill Condon (Gods and Monsters), is in many ways a traditional Hollywood biopic. What makes this tale intense is the degree to which Kinsey’s life was his work—not only in the amount of time he spent at it, but also in the way he used his research to explain and exorcise the demons in his own life.

In developing that point, Condon employs a fascinating and comprehensive expository device: he has Kinsey (Liam Neeson) detail his life through the very interview process he invented. (The film begins with Kinsey off-screen, castigating a member of his team for shoddy interviewing technique.) Together with appropriately placed flashbacks, this Q-and-A format allows us to learn about Kinsey’s lonely and sickly childhood, his mastery of the outdoors (in 1913 he was one of only 77 Eagle Scouts in the U.S.), and his difficult relationship with his dogmatic and demanding father (John Lithgow), an engineering professor and Methodist preacher who would howl about the sins of lust. (In one sermon, he bemoans the invention of the zipper, which “provides every man and boy speedy access to moral oblivion.”)

We also learn about his marriage to his onetime student, Clara McMillen (Laura Linney); the birth of his three children; his insatiable curiosity about all things scientific; and his frustration at the sexual ignorance that surrounds him.

The film then turns to Kinsey’s public life, including the publication of the wildly successful Sexual Behavior in the Human Male (1948) and the less popular Sexual Behavior in the Human Female (1953). (Apparently the public figured that men were always on the prowl, but didn’t want to hear about what their mothers and sisters were doing.)

On the road to fame, Kinsey received funding from the Rockefeller Foundation to create the Institute for Sex Research in 1947, before running into a string of problems, including J. Edgar Hoover, the witch hunt for communists and a stinging attack by Billy Graham, who preached against his effect on “moral purity.”

In portraying this part of Kinsey’s career Condon veers off the biopic road to examine Kinsey’s discoveries about sexuality—people’s longing for additional sex partners in and out of marriage, the desire to explore alternative types of lovemaking and, in Kinsey’s case, the freedom to experiment with bisexuality, which had long been buried by guilt and fear.

The most telling conflict in the film is between sex and love, addressed bluntly in a scene between Kinsey and Clara in which he first admits to a homosexual affair. He defends himself by saying that she is free to explore her own fantasies and desires (he knows what they are, thanks to her interview). This remark leads to a dialogue about the tenuous balance between love and desire, and about how many of society’s restraints are in place not to shackle the human spirit but to prevent people from hurting each other.

Neeson brings energy and intelligence to the role. You can hear his brain crackling as he listens and learns, even when interviewing a pedophile. (This aspect of Kinsey’s story is the most unsettling, and the one that Condon seems least sure how to handle.)

Some viewers will be uncomfortable with the graphic nature of this film, just as there were those uncomfortable with Kinsey’s initial reports. But Kinsey, for all his foibles, flaws and occasional statistical inaccuracies, was a social pioneer and a key figure of the 20th century, and this stylish film does him justice.