Alexei Navalny's memoir to be published in October

A memoir written by Russian opposition leader Alexei Navalny before his imprisonment and death is to be published later this year.

He "wrote the entire memoir himself," publishers Vintage told the BBC.

The anti-corruption campaigner began work on his book while recovering from his 2020 poisoning by the Novichok nerve agent.

Navalny died in February after three years in jail for charges he denounced as politically motivated.

His memoir will be "the full story of his life: his youth, his call to activism, his marriage and family, and his commitment to the cause of Russian democracy and freedom in the face of a world superpower determined to silence him," Vintage said.

The publisher added that it "expresses Navalny's total conviction that change cannot be resisted and will come".

Navalny began writing the memoir while recovering from the poisoning. The book - due out in around six months - is slated to include "never-before-seen correspondence from prison", according to Vintage.

The campaigner and lawyer recounts "his political career, the many attempts on his life, and the lives of the people closest to him, and the relentless campaign he and his team waged against an increasingly dictatorial regime" in the work.

Navalny's widow, Yulia, said: "This book is a testament not only to Alexei's life, but to his unwavering commitment to the fight against dictatorship - a fight he gave everything for, including his life.

"Through its pages, readers will come to know the man I loved deeply - a man of profound integrity and unyielding courage."

She said that sharing his story would honour his memory and "inspire others to stand up for what is right and to never lose sight of the values that truly matter".

Navalny's Anti-Corruption Foundation (FBK) exposed corruption at almost every level of the Russian state - frequently targeting President Vladimir Putin and his entourage.

Navalny was immediately imprisoned after returning to Russia in 2021. He was moved to one of Russia's toughest penal colonies shortly before his death.

According to the prison service, he had gone for a walk when he lost consciousness and died.

One of his closest allies, FBK chief Ivan Zhdanov, said it was "highly likely" Navalny had been murdered.

Vintage described the book as "Navalny's final letter to the world".

The publisher called it an account of his last years spent in "the most brutal prison on Earth; a reminder of why the principles of individual freedom matter so deeply; and a rousing call to continue the work for which he sacrificed his life".

Navalny, 47, was last seen in public the day before his death, looking well and laughing during a court hearing via video link.

The book will be published on 22 October.