Book excerpt: Twenty years after writing Drug Lord, Terrence Poppa decided the information in his book was more important than ever. In an important interview with the Texas Tribune, Poppa explains that ''the Mexico that I wrote about in the book describes the old order of things: Mexico under the PRI. In that sense, the book was out of date, because how drug trafficking operated under the PRI is completely different than how it works today in a new Mexico, under the democratically transformed Mexico...There has been a decoupling of the highest levels of power from drug trafficking now. It's important for people to understand that, so I had to bring the book up to date.''