Compiled genealogies and other sources of previous research provide an excellent starting point for you family history search.
Many countries have bibliographies of published family histories with alphabetical indexes of the major surnames. Recommended examples include:
General Genealogical Bibliography
Marshall, George W., ed. The Genealogist’s Guide. Reprint of 1903 ed. Baltimore: Genealogical Publishing Co., 1980. Read free online at https://archive.org/details/cu31924029579699/page/n13
Whitmore, John B. A Genealogist’s Guide: An Index to British Pedigrees in Continuation of Marshall’s Genealogist’s Guide (1903). London: Walford Bro., 1953.
Country-specific Genealogical Bibliography
French Genealogical Bibliography
Étienne Arnaud. Répertoire de généalogies françaises imprimées . 3 vols. Paris: Berger Levrault, 1978-1982.
Dutch Genealogical Bibliography
Van Beresteyn, E.A. Genealogisch Repertorium. Den Haag, Netherlands: Centraal Bureau voor Genealogie, 1972.
German Genealogical Compendia
C.A. Starke, Deutsches Geschlechterbuch. Limburg an der Lahn, 1889.
German lineage book: An outstanding series for Germany comprising over 197 volumes of collected genealogies (lineages) of thousands of families, often mentioning emigrants.