Many tools have been received to know the history of the Mauryan period.
The most important of which are $44$ records of Ashoka.
Among the other important tools for knowing the history of the Mauryan period is the Economics of Kautilya and the Indica by Megasthenes.
Kautilya's Arthashastra is an important treatise on Mauryan rule.
Kautilya's economics explains the principles of governance, the nature of the state, the duties of rulers and officials, the duties of citizens and relations with foreign countries.
Economics was created by Guru Kautilya of Chandragupta Maurya.
In history he is known as "Chanakya".
The principles of the state and the duties of the king are described in economics.
Chanakya was the mentor of Chandragupta Maurya and Bindusara.
He formulated the "Saptang Siddhanta".
In this treatise, Kautilya vividly depicts his views on the political form of order and statehood.
Kautilya's treatise does not appear to have been written at the same time as it also mentions officials from the time of Emperor Ashoka, indicating how much later it may have been added to the text.
Yet Kautilya's economics is the most important historical material for knowing the state system of ancient India.