Ancestry.com (Chicago, IL): 'how-to' & reference books.

Berrien County Genealogical Society (Benton Harbor, MI)

Booklady Used & Rare Books (Evanston, IL): used and collectible history and genealogical books.

Eaton County Genealogical Society (Charlotte, MI)

Family Heritage (Albion, MI): supplies, gifts, general material.

Family Tree Imports (Lansing, MI): British Isles-Irish 'how-to', guides, maps, history.

Flint Genealogical Society (Flint, MI)

Fossil Tree (Holland, OH): Preservation & scrap book materials.

Genealogical Society of Monroe County (Monroe, MI)

GLYNDWR Resources (Decatur, MI): local & regional publications.

Historical Society of Greater Lansing (Lansing, MI)

Ingham County Genealogical Society (Mason, MI)

Irish Genealogical Society of Michigan (Beverly Hills, MI)

Lapeer County Genealogical Society (Lapeer, MI)

Michiana History Publications (South Bend, IN): used/out-of-print material, mainly Midwest history/genealogy.

Mid-Michigan Genealogical Society (Lansing, MI)

Roger Moffat (Caledonia, MI): genealogical computer software.

Moses Research Group (Lyons, MI): reproductions of old pictures.

Muskegon County Genealogical Society (Muskegon, MI)

Petersen Reproductions (Mishawaha, IN): gifts, supplies, general material.

Shiawassee County Historical Society  (Owosso, MI)

Then & Now Historical & Genealogical Society of Eastern Allegan County (Wayland, MI)

Western Michigan Genealogical Society (Grand Rapids, MI)