This is set in the present day (well, 2000 when first published) and concerns the first contact by aliens, who choose an ordinary middle-aged American woman as their one and only official contact. The story is mainly about the impact this has on her life, but in parallel with that is a contest between two opposed groups. The "good aliens" who make the initial contact are dangling the prospect of membership of an interstellar civilisation provided the Earth tidies up a few odds and ends.... which needless to say involves putting right a lot of social and political problems which we are all too familiar with. Should humanity fail to qualify for membership, they will fall into the hands of the "bad aliens" who want the Earth to become a private hunting preserve - the prey being humans.
There's a lot of fun to be had in the relationship with the good aliens, who are logical and assume that humans mean what they say, leading to all manner of misunderstandings, especially concerning religions. They are also all-powerful - one of their first interventions is in the Middle East where they identify the old city of Jerusalem as the main focus of the problems, so they replace it with a large hole in the ground (dumping the residents unharmed into the surrounding countryside) promising to bring it back undamaged once the inhabitants sort out their differences. Other interventions follow, for example addicts suddenly being unable to tolerate alcohol and drugs.
One feature of the good aliens is that they are all the same until they reach adulthood, when they develop into specialised forms for different roles, as determined by tests carried out at the end of childhood. Some become males or females for breeding, another caste is concerned with bringing up children, some become politicians and so on. That way everyone ends up doing the work to which they are best suited so are (apparently) content with their lives. That might work for hypothetical aliens but I am not as comfortable with this idea for humanity as the author seems to be: it reminds me of Huxley's Brave New World.
Even the good aliens have issues, particularly over their own religion, whose story is told in a huge fresco in a building on their home planet. Over the centuries, the use of smoky candles to illuminate the fresco has completely obscured it, so they rely on descriptions from earlier times to interpret its meaning. When the fresco is cleaned, the aliens discover that the descriptions (inevitably) do not match reality, causing major problems for them.
Tepper was a militant feminist and this becomes obvious as the story continues. The heroine (one to cheer for) has a lot of trouble with her abusive husband and a son who's almost as bad, and the US "pro-life" lobby is savagely satirised. If Tepper were alive today I suspect she wouldn't have much time for the "woke" movement.
Overall, this book is worth reading - Tepper was a natural story-teller and carries the readers along - but she pushes her beliefs so stridently that the balance of the story is adversely affected.