Fiduciary law aspires to nullify power imbalances by obligating strong parties to give themselves over to servient parties. For example, due to profound imbalances of legal know-how, lawyers must as fiduciaries pursue their clients’ interests, not their own, lest clients get lost in the competitive shuffle. As a peculiar hybrid of status and contract relations, politics and law, compassion and capitalism, fiduciary law is very much in vogue in academic circles. As vogue as it is, there remains room for my “Fiduciary-isms...”, a meditation on the expansion of fiduciary law from its origins in the law of trusts through partnerships, corporations, and agency, to a current usage at times so cut off from its doctrinal origins as to be idiomatic,...