You're in luck if your family tree features early German immigrants to Pennsylvania.
Genealogists tracing Colonial immigrants often bemoan the lack
of official passenger lists to help pinpoint their ancestors' arrivals
in America. But not the descendants of German immigrants to Pennsylvania—because that colony's English officials passed laws requiring ship captains to compile lists of their foreign passengers. Immigrants from the British Isles already were royal English
subjects—rather than foreigners—so these invaluable passenger lists are unique to Germans.
The lists have been published in a three-volume work called Pennsylvania German Pioneers (Picton Press, $175). Aside from the obvious benefit of pinpointing an arrival date, these records present a great opportunity for "cluster genealogy":
If you don't know your family's village, look for their shipmates whose hometowns are recorded—they may be your ancestors' neighbors. A good number of the lists show signatures of male immigrants ages 16 and above, which you can compare to wills and deeds to straighten out identities in cases of common names. Some records even give ages and list women and children.