When Gifty is asked by her dates what her neuroscience graduate research entails, she quips that she gets mice hooked on cocaine and then takes it away from them.

This is not strictly true - cocaine is expensive, so she is now getting the mice addicted to Ensure, a nutritional drink.

But behind the glibness lies a gulf of hurt. When she was a child, her brother died of a drug overdose. Her mother, overcome by depression, refuses to get out of bed.

With every mouse Gifty experiments on, she delves a little deeper into the inexplicable workings of the human mind, towards an answer for why her brilliant brother turned from shooting hoops to heroin, why her once-indomitable mother now colonises her bed "like a virus".

Yaa Gyasi, who was born in Ghana and grew up in the United States, made a splash with her powerful debut novel Homegoing (2016), the saga of two half-sisters in 18th-century Ghana - one enslaved, the other marrying into power - and their descendants.

Transcendent Kingdom, her sophomore novel, refocuses that sweeping scope into the parameters of a science experiment, balancing clinical detachment with profound grief.

The novel moves back and forth through Gifty's life - from her misfit childhood in Alabama as the daughter of Ghanaian immigrants - to the micro-aggressions she faces as a young black female scientist at Stanford University.

She has little memory of her father, the Chin Chin Man, nicknamed after the snack he liked. Unable to cope with the discrimination he faced as a black janitor in the US, he went back to Ghana for a visit and never returned.

It is an abandonment Gifty's older brother Nana never quite recovers from. His bright future in sports is derailed when a doctor prescribes him opioid medication for an injury.

"Their kind does seem to have a taste for drugs," remarks a fellow worshipper at the white evangelical church they attend.

Their mother endures drudgery as a carer for the elderly, frets over every cent and thinks saying "I love you" is "white people foolishness".

"My first thought, the year my brother died and my mother took to bed, was that I needed her to be mine again, a mother as I understood it," says Gifty.

"And when she didn't get up, when she lay there day in and day out, wasting away, I was reminded that I didn't know her, not wholly and completely. I would never know her."

Gifty's narrative can verge on didactic - much of it is her thrashing out theological arguments with herself, as she works through her complex relationship with God and the unknowable facets of the universe.

But the novel's brilliance lies in its scalpel-keen precision, as Gifty peels apart the layers of the mind and navigates the fine line between science and faith, searching for that elusive thing called a soul.

If you like this, read: Real Life by Brandon Taylor (Riverhead, 2020, $44.89, available at bit.ly/RealLife_BT), a Booker Prize-shortlisted novel about Wallace, a gay black biosciences research student who feels like an outsider at his mostly white university in the American Midwest.

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