YONKERS - Thousands of fans attended Hillary Clinton's book signing today at Barnes & Noble in Union Square.  

Some admirers arrived 24 hours early and slept outside.

"Hard Choices" discusses the former secretary of state's time in political office, but some say the release of the book is an unofficial kickoff to a possible White House run.

The 635-page book is said to have earned Clinton an $8 million advance.

She will be spending the next few weeks on the road promoting the book.