Working: Researching, Interviewing, Writing by Robert. A. Caro. He is known for his biographies of Robert Moses (The Power Broker) and of Lyndon Johnson, and for his extensive research of these subjects.
Early in the book, covering his early career when he was working as a journalist, one of his bosses gave him a lesson in investigative reporting in a nutshell: Just remember, turn every page. Never assume anything. Turn every goddamned page. The book contains various subsequent examples of him doing exactly that in various research endeavours, and also going to extreme lengths to put himself in a better mindset for writing whatever he is working on at the time, like moving to the area a subject grew up in to live there for a year to better research his early life.
There are examples of him sifting through many boxes of documents in an archive that would seem to be inconsequential, but then happening on a receipt or memo that is just an allusion to something that gives him the lead he needs to uncover some real information.
Early in the book, covering his early career when he was working as a journalist, one of his bosses gave him a lesson in investigative reporting in a nutshell: Just remember, turn every page. Never assume anything. Turn every goddamned page. The book contains various subsequent examples of him doing exactly that in various research endeavours, and also going to extreme lengths to put himself in a better mindset for writing whatever he is working on at the time, like moving to the area a subject grew up in to live there for a year to better research his early life.
There are examples of him sifting through many boxes of documents in an archive that would seem to be inconsequential, but then happening on a receipt or memo that is just an allusion to something that gives him the lead he needs to uncover some real information.