How the Other Half Lives, Jacob Riis (1890).

The Jungle, Upton Sinclair (1906).

The Grapes of Wrath, John Steinbeck (1939).

Unsafe at Any Speed, Ralph Nadar (1965).

What has been the impact of these authors and their books on American society?

- These works had significant influence on social, political, and economic reform.

Explanation:

As per the question, the given authors, as well as their texts, had a quite considerable impact on the social, economic, as well as the political realm of the American society. 'How the Other Half Lives' by Jacob Riis displayed the social evils like poverty, widening gap between the poor and rich, corruption, the terrible condition of the immigrants in slums of New York, etc. while 'The Jungle' authored by Upton Sinclair reveals the economic evil of 'wicked and destructive consequences of capitalism.'

In 'The Grapes of Wrath', Steinback discusses the 'condition of migrant workers and inhumanity faced by them' and 'Unsafe at Any Speed' comments upon the 'dangers of style-oriented behavior of American Automobile industry and ignorance of consumer safety act which makes people unsafe at every speed.' Thus, all four texts display significant issues prevalent in American society at the time.