In the immediate post-Darwin era, the most poignant debates were centred on Man's ascent and/or descent. Lubbock perceived of ancient man as uncivilised intellectually and lacking in any high morality or sentiment. This, we know, today, is not so.
The author was English anthropologist Sir John Lubbock (1834-1913). His book, The Origin of Civilization and the Primitive Condition of Man, draws up an evolutionary trajectory, beginning with atheism and culminating in higher moralities. Much of this is flawed as we know that religion is ancient, and dates back at least to the emergence of Homo Sapiens over 150,000 years ago.
Nonetheless a key book of its time.