Patterns of Affinity introduces, with elegant simplicity, formulas for predicting human inclinations. In order to work, the algorithms require intimate knowledge of the individuals in question: a breadth of information that our mother could acquire only in a remote, insular community where the history of each member was known to all the rest. At the book’s conclusion, she speculates that her formulas’ predictive powers could, theoretically, be applied to people living in a complex, mobile environment … but doing so would require exhaustive personal information that would be impossible to acquire in a modern setting without posing an array of intrusive questions whose answers few people, if any, would be willing to supply.