Author of Twitter best-seller working on Silk Road book 

The author of a best-seller about Twitter is working on an investigative book about the black market website Silk Road.

New York Times columnist Nick Bilton has a deal with Portfolio for a "detailed narrative," the publisher announced Monday. The book is currently untitled and no publication date has been set. Authorities have said Silk Road's San Francisco operator generated more than $1 billion in illicit business from 2011 until the website was shut down in 2013.

According to Portfolio, Bilton has been looking into Silk Road for the past year, in coordination with Epic Magazine. 20th Century Fox has acquired rights to a Silk Road film based on Bilton's book and Epic's planned story.

Bilton's previous book, "Hatching Twitter," came out in 2013.