Resources

Preservation Organizations (National/International):

Association for Preservation Technology International (APTI) 
DOCOMOMO, US chapter
International Centre for the Study of the Preservation and Restoration of Cultural Property (ICCROM) International of Concrete Repair Institute (ICRI)
National Council for Preservation Education
National Preservation Institute
National Trust for Historic Preservation
Society for Industrial Archeology
United Nations Educational, Scientific, and Cultural Organization (UNESCO)
World Monuments Fund

Organizations Who Maintain Lists of Preservation Consultants and Contractors:

CT Trust for Historic Preservation
Preservation MASS
New York Landmarks Conservancy
Preservation Rhode Island
New Hampshire Preservation Alliance

Preservation Organizations (Metro New York):

DOCOMOMO, New York/Tri-state chapter
International of Concrete Repair Institute (ICRI), Metro New York Chapter
Historic Districts Council
Historic House Trust
Historic Hudson Valley
New York Landmarks Conservancy
New York Preservation Archive Project
Preservation New Jersey

Preservation Organizations (beyond Metro New York):

Boston Preservation Alliance
Boston Society of Architects Historic Resources Committee
Women in Restoration & Engineering (Boston and Chicago) 
Historic New England