A major revision of the FRCP in 1966 radically transformed Rule 23, made the opt-out class action the standard option, and gave birth to the modern class action. Entire treatises have been written since to summarize the huge mass of law that sprang up from the 1966 revision of Rule 23. Just as medieval group litigation bound all members of the group regardless of whether they all actually appeared in court, the modern class action binds "all" members of the class, except for those who choose to opt out (if the rules permit them to do so).