The US National Park Service provides the only national level programs, information, and guidance about historic preservation. Two main resources are:
The National Park Service develops and publishes a series, “Preservation Briefs,” which offers free on-line best practice information on fifty different preservation topics.
This office has established four “treatments” of historic properties that are national standards for working on/with historic structures: Preservation, Rehabilitation, Restoration, and Reconstruction.
Often the general public assumes that ownership of a historic structure restricts the work and treatments they can do by law. This is not true. Unless you are applying for IRS Tax Credits these guidelines are advisory, not regulatory. They identify best practices in historic preservation.
National Register of Historic Places
This office is part of the National Park Service; however, applications for the National Register of Historic Places designation begin with the State Historic Preservation Office. Application instructions and forms are available from the Michigan SHPO and are first reviewed there (see SHPO under State Resources).