"I am going to live authentically for the first time in my life," she writes of how she felt after undergoing the procedure, where the penis and testicles are removed and the remaining skin is surgically repaired to create a vagina and clitoris.
"I am going to have an enthusiasm for life that I have not had in 39 years since the Olympics, almost two thirds of my life."
The highly anticipated tell-all book is set to be released on April 25.
Jenner will also embark upon a US-based book tour in the upcoming weeks.
This article previously appeared on WHO.