"However, these hidden layers are like a locked black box: we see the input and output, but what is happening inside is not clear," says Danilo Vasconcellos Vargas, ...

Initially prevalent in the U.K. and Asia, the locked box approach is gaining traction in the United States due to the growing demand for expedited M&A transactions and a robust seller's market.

The Harvard historian uses the black box in his new book as a metaphor for how African Americans were once “locked in” when it came to expressing themselves in writings.