Pebble in the Sky is not a great novel. However, as the first published one of Asimov's vast body of work, it is interesting in its flaws and strengths. Set in an underpopulated Earth tens of thousands of years into the future, the tale features an unlikely hero, the immigrant Joseph Schwartz, an old Chicago tailor from the 20th century. Through accident, he is hurled in time to arrive at the outskirts of Chica, the name for the Chicago area in the future. Instead of an Earth teeming with billions, Earth suffers from extreme areas of radioactivity, a dystopian government (yet still a part of the Galactic Empire ruled from Trantor) with productivity quotas for each inhabitant (not to mention the mandatory killing of everyone aged 60) and a conspiracy that threatens to destroy the entire Empire.
Our unlikely hero, who is often passive throughout much of the novel, is a plump tailor who becomes the unwitting specimen for Dr. Shtek's Synapsifier, which somehow improves Schwartz's mental faculties and gives him telepathic powers. Along the way, the reader is treated to various digressions that all connect to the unbelievable theory of the Secretary of the High Minister of Earth's native government, who thinks Schwartz and Arvardan are spies sent by the Empire to ensure Earth's submission. Later, and somewhat randomly, the more menacing (and truthful) conspiracy of Earth against the rest of the Galaxy is revealed. Where the novel succeeds is in the world-building elements. The plot is zany, and the other characters besides Schwartz are usually more interesting or compelling (particularly the archaeologist Arvardan, who knows Earth is the original homeland of humanity and wants to prove it). For much of the narrative, Schwartz is often forgettable. And when he does, inevitably, save the day, Schwartz, like his role in much of the narrative, accomplishes this in the background. However, the novel persuasively builds a world in which the people of Earth are dismissed and hated by the rest of the Galaxy, believed to be carriers of dangerous bacteria and even a separate race.
It is in this direction where Asimov seems to be drawing from the divisive issues of race in his day to point out the fallacy of racial and racist thinking. Arvardan, for instance, argues firmly against the idea of Earthmen as racially distinct, while also rejecting the idea of polygenesis. Instead of believing the humans of the Galaxy all evolved independently on several distinct planets, the more likely (and correct) theory of monogenesis and the oneness of humanity unites Earthmen with the rest of the Galaxy. However, Arvardan must confront his own prejudices and biases against Earthmen on a personal as well as academic level, distinguishing himself from the bigoted Imperial garrisons and representatives who look down on Earth natives are savage, violent, and untrustworthy. One must conclude Asimov was thinking of ongoing Jim Crow in the US and the recent experience of World War II and the Holocaust, two areas where racial thinking and racist policy carried devastating consequences for the world. It is perhaps for that reason he decided to make an old European immigrant tailor from Chicago a hero, one who was probably Jewish like the author.
While the novel itself is nothing spectacular, it deserves attention for its unusual protagonist, the large ensemble cast of characters Asimov struggles to balance in the narrative, and the persistent thorny issue of racism and misunderstanding as causes for catastrophe. Of course, it's also an indispensable part of the Empire books, and features the Empire of Foundation in an era before its decline. One wonders why the effete imperial agent in the Foundation series, with an amateurish interest in archaeology and the study of human origins, did not know of the research of Arvardan and his conclusive proof of Earth as humanity's homeland...