The father of Becky Watts will describe the "devastation of discovering the truth" about his daughter's death in a new book.
Darren Galsworthy's book, entitled Becky, will be published exactly a year since her dismembered remains were discovered, on March 3.
In the 304-page memoir Mr Galsworthy describes Becky's relationship with her stepbrother, Nathan Matthews, 28.
Matthews murdered Becky after hatching a sexually-motivated kidnap plot to kidnap her with his girlfriend Shauna Hoare, 21.
The couple, who shared an interest in petite teenage girls, let themselves into 5ft 1in Becky's home in Crown Hill, Bristol, on February 19.
She suffered more than 40 injuries before being suffocated by Matthews, then was bundled into the couple's car.
Her body was dismembered in their home in Cotton Mill Lane, Bristol, and was discovered by police in a nearby garden shed.
The £12.99 book will be published by HarperNonFiction, which describes it as a "heartfelt and powerfully affecting tribute" to Becky.
Mr Galsworthy said: "I want people to know what Becky was really like - she was big-hearted, fearless and incredibly generous.
"On behalf of myself and my wife, Anjie, I also want to tell the full story of what we have been through as a family.
"Becky was loved unconditionally and her life was cruelly taken from her in the most horrific way - by somebody we all trusted.
"This book will serve as a lasting tribute to my beautiful daughter, who I will always be proud of."
In November, former TA soldier Matthews was convicted of Becky's murder and jailed for a minimum of 33 years.
Hoare was jailed for 17 years after being found guilty of Becky's manslaughter. Both were convicted of conspiring to kidnap her.
The verdicts came following a five-week trial at Bristol Crown Court - a "torment" Mr Galsworthy writes of in the book, HarperNonFiction said.
Mr Justice Dingemans was in tears as he paid tribute to Becky's family and spoke of the "immense burden" the trial had placed on them.
Vicky Eribo, editorial director for HarperNonFiction said: "Becky's murder shocked the nation in a unique way.
"The pain and heartbreak Darren must be suffering at this time is unimaginable, but I believe this is a story that needs to be heard.
"Throughout the trial Darren and his family were praised by the judge for their incredible dignity in the circumstances.
"In this haunting book Darren brings the same unflinching honesty and integrity to every word he writes about his daughter as he pays tribute to the adored child who brought joy to all who knew her.
"We feel incredibly privileged to have the opportunity to work with Darren and help him take back control of the way Becky's short life is remembered."
Both Matthews and Hoare have applied to appeal against their convictions and sentences.