More precisely, the book, titled "Clinton Cash," was written by Peter Schweizer, a former fellow at the conservative think tank Hoover Institution. His past work while at the think tank can be found here.
Here is more on the Hoover Institution by Ade Adenji, who just wrote a piece for Inside Philanthropy entitled "How the Hoover Institution Vacuums Up Big Conservative Bucks":
Like AEI, Hoover might be described as a moderate conservative think tank—in contrast, say, to the Heritage Foundation and other policy shops that push a harder line and have been aligned in recent years with the Tea Party.
Hoover's moderate positioning makes sense, since Herbert Hoover himself was certainly no doctrinaire conservative and even considered being a Democrat at one time. The Hoover Institution's mission includes principles such as "representative government, private enterprise, peace, and personal freedom" and senior fellows at the institution have included Condoleezza Rice, economist Thomas Sowell, and author Shelby Steele.
Hoover, which is housed within Stanford University, was just ranked as the 19th best think tank in the United States by the University of Pennsylvania think tank rankings. It was also considered the 4th best university-affiliated think tank in the world.
So, will a sole think tanker bring down the entire Clinton campaign?
Here is Think Tank Watch's most recent piece on Hillary Clinton's use of think tanks.