In a new book released Tuesday, former Pakistani Prime Minister Benazir Bhutto says she was optimistic about her return to Pakistan, but knew about the dangers to her life.

The slain opposition leader's final book, Reconciliation: Islam, Democracy, and the West, was finished shortly before her assassination. In it, Ms. Bhutto says she had been warned that four separate suicide bomber squads had been sent to kill her, including one led by the son of al-Qaida leader Osama bin Laden.

Ms. Bhutto was killed on December 27, just weeks after she returned from eight years in exile. She made the last few edits to her book the day she died.

The former prime minister writes that she hoped to be a catalyst for change in bringing democracy to Pakistan. She also calls for a reconciliation of Islam with democratic principles, despite opposition from extremists.

The book is being published several weeks ahead of schedule. It includes an afterward by Ms. Bhutto's husband, Asif Ali Zardari, and her three children.