On The Foundation for Individual Rights and Expression's web site there's an article about
a legal action being brought in the state of Oregon by free speech and animal rights organizations. The suit is about making surreptitious audiovisual recordings of, in this case, animal abuse:
“The modern-day Upton Sinclair would not conduct his landmark investigation into Chicago’s meatpacking plants relying solely on his written notes, based on memory, and transcribing them into a book,” said Chris Carraway, Staff Attorney at the Animal Activist Legal Defense Project, referring to Sinclair’s groundbreaking work, The Jungle.
Possibly there's a point in there somewhere, but I'm guessing the good staff attorney has never read the book. It's a highly readable and currently relevant novel, an investigation of the brutal treatment of immigrant labor in Chicago in the 1920s. The meatpacking industry is simply the setting for the story.
The reading public, it turned out, was far more interested in the safety of their meat than in the plight of the workers, so that's what the book is remembered for.
And it did, indeed, lead to substantial reforms in the industry.
And Sinclair did, in fact, rely on written notes and his memory.
A digital copy of The Jungle can be obtained free from Project Gutenberg, or for $0.99 at Amazon.