Bitter Rivals illuminates the essential history - and profound ripple effect - of Iran and Saudi Arabia's power struggle. It draws on scores of interviews with political, religious and military leaders, militia commanders, diplomats, and policy experts, painting American television's most comprehensive picture of a feud that has reshaped the Middle East.

• BBC Arabic
• Ali Khamenei
• Prince Mohammed bin Salman al Saud
• Turki Al-Faisal
• Bashar Hafez al-Assad
• Mohammad Javad Zarif
• Adel Al-Jubeir
• Martin Smith