Jose Baez and Casey Anthony
Splash News Online; Landov
Casey Anthony's lawyer Jose Baez says she lived in a "fantasy world" in his soon-to-be-released book
In Presumed Guilty, Casey Anthony: The Inside Story
, Baez writes that Anthony's lies to police weren't proof of her guilt but, instead, revealed someone who had "serious mental health
issues," according to a copy obtained by the Associated Press.
"I wrote the book because there was so much that people didn't know, and still don't know," Baez tells PEOPLE. "This book is more than 420 pages of nothing but the inside story. I think people's reaction will be surprised at how much they don't know. My goal wasn't to change anyone's minds. My goal was to tell the story and if people change their minds, it will be because [they learned] more facts."
For instance, describing in the book why the Florida mother took police officers to Universal Studios to look for her daughter, Caylee, Baez writes that detectives should have realized, " 'Wait a minute, we're not dealing with someone who is playing with a full deck.' "
Anthony originally told police that Caylee was taken by a babysitter and that she had been searching for her for more than a month before reporting Caylee missing.
During the trial, Baez argued that Caylee accidentally drowned in the family's swimming pool while Casey and her father, George, were at home, and that George allegedly hid the body. (George denied the defense's allegations that he was involved in and covered up Caylee's death.)
Baez also details in the 421-page book (out July 3) why Casey never testified at her own trial.
"We had everything to lose and very little to gain," he writes.
In it, he also criticizes the media, Prosecutor Jeff Ashton and some of Judge Belvin Perry's rulings, though he does appreciate the fact that the judge allowed him to pick a fair jury. Baez also reveals that Casey had a cheeseburger, French fries and milkshake from Steak 'n Shake for her first meal after being released from jail.
Then, he writes, she flew via private plane to St. George Island on the Florida Panhandle before going to New York. Anthony is now in Florida
serving her probation sentence
For more from our exclusive interview with Jose Baez, pick up next week's issue of PEOPLE