Step 1: Understanding the Concept:
Ancient Indian history is often reconstructed using accounts of foreign travelers. The book {Indica} is a primary source of information regarding the Mauryan Empire.
Step 2: Detailed Explanation:
1. Megasthenes was a Greek ethnographer and explorer in the Hellenistic period.
2. He was sent as an ambassador by the Greek ruler Seleucus I Nicator to the court of Chandragupta Maurya, the founder of the Mauryan Empire.
3. In his book {Indica}, Megasthenes described the Indian subcontinent, its climate, soil, flora, fauna, and specifically the administration of the capital city, Pataliputra.
4. Although the original text is lost, its fragments survive in the works of later writers like Arrian and Strabo.
5. Other authors mentioned: Kautilya wrote {Arthashastra}, Visakhadatta wrote {Mudrarakshasa}, and Pliny the Elder wrote {Naturalis Historia}.
Step 3: Final Answer:
The book {Indica} was written by Megasthenes.