The Buffalo City Directories run almost continuously from 1832 until WWII and are an important resource for genealogical researchers in Buffalo. The directories usually list heads of families or householders along with their occupation and address. Later directories may list all adult members of each family.
A survey of the directories should be the starting point for any City of Buffalo research. Begin with a year when you know your family was in the city. Work backward and forward copying all entries for your surname until you don't find any more. This technique can produce a good outline of a family and the addresses can be used to help find other records such as census records and church records.
A transcript of the 1828 Buffalo City Directory is now available on-line. This was the first directory published but apparently few or no copies have survived. It was reprinted in the back of the 1876 directory. Also of interest is a table of occupations along with the number of entries for each and a table showing the number of directory entries for each street.