Though the title makes men­tion of infi­deli­ty, this book is about fideli­ty to one’s past, about keep­ing sto­ries alive and try­ing to under­stand them. Many of Katharine Weber’s fam­i­ly mem­bers are woven into the nar­ra­tive, but the author, best known for her nov­el Tri­an­gle, has cho­sen to focus on her father, Sid­ney Kauf­man, and her mater­nal grand­moth­er, Kay Swift. Both are long deceased, and Weber her­self is in her mid-50s — she seems to be dig­ging deep to write defin­i­tive­ly about all that is no more in her family.

Swift gets top billing, along with her long­time lover George Gersh­win, but the first por­tion of the book is devot­ed to Kauf­man, a seem­ing­ly accom­plished scoundrel whose life appears to have been a mix of illu­sion and delu­sion. Kauf­man came from immi­grant par­ents and end­ed up in the film indus­try, though large­ly on its mar­gins — you won’t find his name in many cred­its (“Most of my father’s movie career took place at the inter­sec­tion of mak­ing it and mak­ing it up,” Weber writes). As described here, he was a ter­ri­ble hus­band —unfaith­ful and total­ly lack­ing in empa­thy for his very pas­sive wife. His rela­tion­ship with his only daugh­ter was based on his being reli­ably unre­li­able, at least, that is, until he stopped talk­ing to her altogether.

The book takes a sharp turn when Weber switch­es her focus to her grand­moth­er, who mar­ried a War­burg before falling for a Gersh­win. Their romance last­ed a decade and was not ful­ly over at the time of the composer’s trag­ic death. (Weber has much of inter­est to say on the hor­ri­fy­ing cir­cum­stances of his demise.) A tal­ent­ed musi­cal fig­ure in her own right, Swift moved in glam­orous cir­cles and lived a fas­ci­nat­ing life, though ulti­mate­ly she didn’t do that much par­ent­ing, either. Still, Swift’s vibran­cy comes across as a wel­come coun­ter­bal­ance to Kaufman’s personality.

The book is chock full of inter­est­ing sto­ries well told. Weber makes it clear that the events she por­trays, even the ones that hap­pened before her birth, are both key to under­stand­ing who she is and also worth remem­ber­ing for their own sake.