The Abbess of Crewe is about the political manoeuvering of Alexandra, who has recently been elected as the head of the Abbey of Crewe. In the first few pages we learn that her ancestry is impeccable, "fourteen generations of pale and ruling ancestors of England, and ten before them of France", she has electronically bugged the Abbey to listen to the nuns's conversations, and she has a secret, "most profitable pact" with the Jesuits. She also has a plan to discredit Felicity, the only other contender for the position of Abbess, which unexpectedly results in an "international newspaper scandal." The remainder of the book explains what happened, how it started "merely from the little misplacement, or at most the theft, of Sister Felicity's silver thimble".
Muriel Spark's book is short, humorous and littered with extracts of poetry. It's not laugh-out-loud funny, but rather farcical in its treatment of the political shenanigans of the players. The titular Abbess embodies the privilege of the elite. They believe the "rules" don't apply to themselves and are ruthless in the pursuit of their ambitions. Alexandra will stop at nothing to get what she wants, has no pity for those who stand in her way, such as Felicity, and is willing to make scapegoats of her supporters, such as Winifrede. It's considered to be an allegory of the Watergate scandal of the 70s but it also brings to mind the political antics of some leaders today.