Read it because it was listed as one of Adichie's favourite books.
The story is somewhat like 'Things Fall Apart' in that it narrates a story of the rise and, later, fall of a man due to values changing under a challenge from colonial rule - only this time it was a religious leader, instead of a warrior/farmer.
The reading experience was greatly enhanced from my having read Carl Jung's 'Man and His Symbols'. To begin with, Jung had much to say about the masks and their impact on personality and the group dances in which everyone seems to be in frenzy. I bet Jung would have loved the book - especially the relationships between the people in the book and their gods.
The protagonist, Ezeulu is constantly holding conversations with his god - which might be called hallucination but Jung would have called it conversing with one's collective consciousness. Because apart from these conversations with his god, Ezeulu can be considered normal. Moreover, people actually want him to hold conversations with the god
Even more interesting is the way in which people can discard gods who have failed to behave aptly and accept the protection of new gods. Gods do not have the right to punish people unjustly. This change of gods according to needs of society seems to correspond to Jung's ideas - the change in conscious beliefs for the 'primitive' tribes to be in harmony to change in needs of their collective unconscious. Jung believed that most of the modern people's existential crisis arises exactly because of the lack of such harmony.
And there are of course proverbial expressions which is one of the best things about Achebe's writings:
"A man might pick his way with the utmost care through a crowded market but find that the hem of his cloth had upset and broken another's wares; in such a case the man, not his cloth, was held to repair the damage."
"He forgot the saying of the elders that if a man sought for a companion who acted entirely like himself he would live in solitude."
"A man who asks questions does not lose his way."