Riley Keough, granddaughter of Elvis Presley, has revealed how she “burst into tears” as she listened to tapes her late mom left behind to finish her memoir, People reports. The book, From Here to the Great Unknown, which is due to be released in early October, will give a peek into the life of Lisa Marie Presley, who died last year at the age of 54. In an excerpt, Keough, who completed the book, reveals how she had been afraid to hear her mother’s voice after “months of grief.” “I began listening to her speak. It was incredibly painful but I couldn’t stop. It was like she was in the room, talking to me. I instantly felt like a child again and I burst into tears. My mommy. The tone of her voice.” In an interview with People, which is releasing excerpts from the memoir, Keough said her mother was “constantly talked about, argued over and dissected,” and that the memoir seeks to “reveal the core of who she was.”