Although some original records such as grants of nobility still exist, you can often research your noble ancestors by using compiled sources. German nobility was frequently associated with the military (officers) and a mobile lifestyle. When the family moved frequently, compiled sources become especially helpful. The compiled sources for German nobility include both published and manuscript genealogies. If your ancestor was of the noble class, the following books may help you in your research:
Hefner, Otto Titian von. Stammbuch des blühenden und abgestorbenen Adels in Deutschland (Lineages of flourishing and extinct nobles in Germany). Four Volumes in Two. Regensburg, Germany: Georg Joseph Mainz, 1860-1866. [https://www.familysearch.org/search/catalog/294814
?availability=Family%20History%20Library (FHL book 943D22h; film 491,136 '''online.'''] This is a quick reference list of German noble families.
Fritsch, Thomas, Freiherr von. Die Gothaischen Taschenbücher, Hofkalender, und Almanach (The gotha pocketbooks, calendar and almanac). Limburg/Lahn, Germany: C. A. Starke, 1968. (FHL book Ref 943 B4da Volume 2.) A comprehensive index of four published serial son German nobility is found on pages 187 to 349. Pages 350 to 415 index six other published serials on German nobility. Führende Persönlichkeiten (Leading personalities). See the “Genealogy” section.