Book of Light is a holy Saradominist book that contains verses which idolise Saradomin and his might in some way, similar to Saradomin's book of wisdom. The Missionary apparently read this book so much that he memorised the transcript of the book and he uses it to support his ideas. This book cannot be obtained by players.
- "In yielding do we find succour, and strength with the new dawn."
- "Saradomin's light is strongest in the dark."
- "Saradomin brought light to plants and beasts of the field."
- "There was no light in their eyes, and the lack of hope was their downfall."
- "But even when the rivers flow away from Saradomin, they cannot deny their source."
- "And the enemies of Saradomin gathered in the shadows but Saradomin's light exposed their schemes and they suffered a great and terrible vengeance."
- "When the white rain comes, the fleets of our enemies will be sunk."
- "The love of Saradomin is ever-forgiving."