Family cookbooks are collections of recipes, sometimes including family history and photos of the family members. These cookbooks may be written in notebooks, put in ring binders, or professionally published by one of several cookbook publishers that cater to families interested in preserving their food heritage.
Families interested in genealogy sometimes also decide to preserve their recipes, since those recipes often represent a facet of their history. Some older recipes may give clues as to the ethnic origins of the people who cooked it, like lebkuchen with its German origins or sweet potato pie and its southern United States roots. Other genealogical clues may be found in recipe boxes, from the things the recipes are written on: old bills (may indicate where a family lived), letters (may contain stories about what was happening in their lives at the time), or newspaper clippings (may have dates).
Other than the historical/genealogical aspect of a family cookbook, they also serve as a way to pass along family traditions to another generation. It is worth the time to measure the ingredients of a cook who makes her/his dishes from memory, as they prepare it. Some recipes may become lost when the person who always made that recipe (from memory) dies if it's not written down. In addition to the recipe itself, stories about the tradition are also good to include, perhaps special Christmas cookies were set out for Santa Claus for many generations, or a traditional Irish meal was made every St. Patrick's Day.
For large families who need to print 100 or more copies of their cookbook, there are several publishers who specialize in printing limited numbers of books. Smaller families have the option of going to their local printer (such as Kinko's), or doing it at home with desktop publishing.