The Lions of Fifth Avenue by Fiona Davis

In 1913, Laura Lyons lives with her aspiring-novelist husband, Jack, and two children in the main branch of the New York Public Library, a perk of Jack's job as the superintendent. Laura has her heart set on attending the school of journalism at Columbia University, if they can just find the money for tuition.  Once she does, Laura begins writing about women's rights in the city. However, there have been a series of thefts of valuable books at the library and the family comes under suspicion. An alternating storyline tells the story of Laura's granddaughter, Sadie, who in 1993 has a position at the same library in the rare book room. Sadie has kept her family connection to the library secret, but when books again go missing, Sadie feels she needs to delve into the past to see if there's any connection between the crimes in order to save her reputation, the precious books, and her job.