The 352-page book, titled Presumed Guilty: Casey Anthony: The Inside Story, will hit bookstores in July – a year after Anthony was acquitted of murdering her 2-year-old daughter, Caylee.
"Casey will not financially benefit from this book in any way, shape or form," Baez tells PEOPLE. "This is my story, not hers."
According to Baez, the book will tell how he became involved in the case and will walk the reader through the defense strategy. He promises it will tell the behind-the-scenes story of the trial that riveted the nation in 2011.
The book also will talk about Baez's relationship with Casey and his observations of her family. And it will give details about her release from jail, and why he stopped representing her.
A Controversial SubjectNews of the book deal has caused controversy, with hundreds of boycotters taking to Facebook and Twitter to urge the publisher, BenBella books, to reconsider the book's release.
Baez insists that Presumed Guilty is not a book about Casey's guilt or innocence, but rather his experience as a key player in the most sensational trial in recent memory.
"I was there from day one," he says. "Other than Casey, no one else was there from the very beginning. These are my insights into what happened."
Although Baez no longer handles Anthony's legal matters, he is still in touch with her as she finishes out her yearlong probation in an undisclosed Florida location.
According to her probation reports, she remains broke and unemployed. After several months of counseling at a church in Palm City, Fla., she has moved on and is no longer receiving therapy. Still, Baez claims that Anthony is fine with his book.
"Casey has authorized me to write it," he says. "I have her complete and total permission."
It's the second book from one of the lawyers involved in the case. Prosecutor Jeff Ashton released his book about the trial, Imperfect Justice, in November. Ashton's book will be made into a Lifetime movie starring Rob Lowe.