Between 1871 and 1910 more than 2.3 million Russian immigrants arrived in the United States, some 600,000 between 1871 and 1898 and 1.7 million between 1899 and 1910. Of the Russian emigrants who arrived in the U.S. between 1899 and 1910, 43 percent were Jews, 27 percent Poles, 9 percent Lithuanians, 8 percent Finns, 5 percent Germans, and 4 percent indigenous Russians. The first six volumes of Migration from the Russian Empire (see numbers 6601 through 6606 below) cover the period from January 1875 through June 1991 (the work will eventually comprise numerous volumes and extend to the year 1910). Volumes 1 through 6 contain data on 290,000 persons of Russian nationality who emigrated to the United States from Russian territories. The information was extracted from the original ships' passenger lists held by the Temple-Balch Center for Immigration Research. These passenger lists--customs passenger lists and immigration passenger lists, as they are known--are the only records that furnish proof of the arrival in the United States of all 2.3 million immigrants from the Russian Empire. For researchers investigating their Russian family origins, this type of information is the very bedrock on which all American family history is built. As borne out in this volume, in scarcely more than a year (June 1889-July1890) an additional 90,000 Russian immigrants flooded into Ellis Island and the lesser ports of entry as the pressures to leave Czarist Russia intensified.