Why Now For The 'Clinton Cash' Book?

Whether accurate or not, the new book titled 'Clinton Cash' paints the picture of a family involved a lot of potentially shady and perhaps(?) quid-pro-quo deals while Hillary Clinton was Secretary of State.  Deals involving wealthy foreigners, foreign companies, and countries that contributed to the Clinton Foundation.  Supporters of  Bill and Hillary are quick to point out that the book was written by former Bush speechwriter Peter Schweizer as the reason to believe its just another "political hit" job by a biased GOP writer. Thus, we are not supposed to trust even a single word that appears in that book.

But, the possibility that it may be a "political hit" job leads us to a very interesting question:  Why now?  We are months away from the nomination and more than a year away from the November 2016 Presidential election.   Why not hold the book until just before the election where it could do some real political damage to Hillary?  That, of course, assumes she will be the Democrat nominee.

I personally think that the book's current release has the sole intended purpose of  hurting Hillary so much that she won't receive the nomination.  I believe that there are some in the Republican party who believe she is unbeatable because of her being a woman and that many Americans feel it is time for the first woman President.  Also, many believe she should have beaten Obama in 2008.  Thus, this book is a defensive move to insure someone else jumps into the race and wins the nomination.  Just my opinion.

References:

New Book, 'Clinton Cash,' Questions Foreign Donations to Clinton Foundation: http://www.nytimes.com/2015/04/20/us/politics/new-book-clinton-cash-questions-foreign-donations-to-foundation.html