The “Nova” (7 p.m., PBS, check local listings) presentation “Forgotten Genius” profiles Percy Julian, a giant of 20th-century chemistry.

A story of intelligence, inspiration, hard work, discipline and perseverance, “Genius” is also a tale of cruelty, stupidity and blind intolerance. Julian was a black scientist trying to make his way in an era of segregation and fought obstacles at every turn.

Born in 1899, only one generation removed from slavery, he became the first black American to receive a master’s degree in chemistry. He would have to go to Vienna to earn his Ph.D.

As “Genius” makes clear, Julian’s woes did not end when he left the segregated South. Institutions from Harvard University to Dupont Chemical slammed their doors in his face. Faculty politics drove him from hospitable black institutions, including Howard and Fisk Universities. Julian’s brilliance and success was an affront to an American scientific and academic community that was not only casually racist but embraced theories of white racial superiority well into the 20th century.

He had to forgo a job at a firm when it became known that the factory town did not permit black residents. This was in Wisconsin, not Mississippi. At the height of his career, he and his family moved to the posh and supposedly enlightened Chicago suburb of Oak Cliff, only to see his house torched by arsonists and his children terrorized by dynamite.

Despite publishing some of the most important papers in his field, Julian could find a job only at Glidden, a Chicago paint manufacturer. But he used Glidden as a base at which to branch into other, more lucrative endeavors. Julian would leave Glidden with more than 100 patents, and his labs would help revolutionize medicine with synthetic steroids and processes that made cortisone widely available to arthritis sufferers.

A less-than-elegant combination of a Black History Month lesson and a primer on the history of American chemistry, “Genius” proceeds at a deliberate pace. It’s at least a half-hour too long.

One hopes “Genius” might inspire a feature-film treatment of Julian’s story, or perhaps a major published work. As “Genius” makes clear, his story has fallen into obscurity since his death in 1975. No popular or scholarly biography of Percy Julian exists. “Genius” is a flawed but inspired beginning.

Tonight’s other highlights

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¢ Auditions continue on “American Idol” (7 p.m., Fox).

¢ Richard recuperates on “Gilmore Girls” (7 p.m., CW).

¢ On two episodes of “The Unit” (CBS), North Korea (8 p.m.), Iran (9 p.m.).

¢ House fights for his parking space on “House” (8 p.m., Fox).

¢ A historic re-enactment has an all-too-real aftermath on “Law & Order: Criminal Intent” (8 p.m., NBC).

¢ A snapshot helps the team trail a predator on “Law & Order: Special Victims Unit” (9 p.m., NBC).

¢ A judge sues because he has not been “cured” of his urges on “Boston Legal” (9 p.m., ABC).