Superlative adjectives normally take the article the.
- She is the tallest girl in the class. (NOT She is tallest girl in the class.)
- This is the best book I have read. (NOT This is best book I have read.)
- Greenland is the largest island in the world.
- You are the most miserable creature in the whole universe. (NOT You are most miserable …)
When superlative adjectives or adverbs come in the predicative position, ‘the’ is sometimes dropped in an informal style.
- Which of these boys is the smartest?
- Which of these boys is smartest? (informal)
‘The’ is not used with superlative adjectives or adverbs used in predicative position when we compare the same person or thing in different situations.
- He works hardest when he is doing something for his children. (Here we are comparing a man’s work in different situations.) (NOT He works the hardest…)