What is a gentleman, and why should every man aspire to be one? Does the ideal still have any value in the age of feminism, "toxic masculinity," and "men going their own way"? Traditional books on manners and gentlemanly behavior have always claimed that manhood is defined by certain universal principles. But these norms have now changed so radically that the standard advice, tried and true as much of it remains, requires new formulation to be...