Federal agencies love to publish guidance documents—those official “statement[s] of general applicability and future effect, other than [regulations]” that set forth “a policy on a statutory, regulatory, or technical issue or an interpretation of a statutory or regulatory issue.” They “come in a variety of formats and names, including interpretive memoranda, policy statements, guidances, manuals, circulars, memoranda, bulletins, advisories, and the like,” and some agencies may even offer guidance “in new and innovative formats, such as video or audio tapes, or interactive web-based software.” Scholars have repeatedly indicated that “[g]uidance documents greatly outnumber legislative rules” and are issued “in a volume dwarfing the [underlyi...