By Blood by Ellen Ullman

This book is set in 1974 and that is critical for two reasons.  One is that the main characters date back to WWII and Nazi Germany, so in order for them to be yound enough for the story to work, the setting has to be in the 1970's.  The other is that the ability to access information needed to be what now seems almost farcically difficult--in the pre-Internet era, that was certainly the case.  Information was in paper formats and required humans to access data banks of infromation.  Requests for information were sent in the mail.  An individual's ability to research their past on their own was far more limited than it is today.

The set up is somewhat classic--a banished academic who's fate is being determined by a university disciplinary committee has fled the state and headed for San Francisco, ostensible to work on the ancient Greek play The Eumenides.  Hopefully his future does not depend on his progress with the project because as far as the reasder knows, he does very little in that regard.  The office next to his is inhabited by a psychotherapist and when her white noise machine is turned off he can hear her therapy sessions perfectly. He becomes obsessed with one particular patient, and adoptee, like himself, who feels unloved by her family and wants to find her birth mother.  The professor uses his academic resources to help her search--doing so anonymously, and then he easedrops on her results.  It is not a happy story, her having a Jewish mother and this being WWII.  While the professor himself is unlikable, the story is well written and it is a great example of how trauma ripples across generations.