Before Yisroel Ba'al Shem Tov there were three Ba'alei Shem: Eliahu Ba'al Shem, Yoel Ba'al Shem, and Adam Ba'al Shem.
"Ba'al Shem" means "master of the Name (of God)." By the power of the Divine Name the Ba'al Shem works miracles, especially to heal the sick.
The Ba'al Shem Tov is the master of the goodly Name, the Name of God Tov (טוב), which means "good" and whose gematria is 17. This is the Name alluded to in the very first verse of the Torah, the Name (Divine power) that unites heavens and earth, spirituality and physicality. Yisroel (Israel, the proper name of the Jewish People) Ba'al Shem Tov came to better (to do good to) our lives, to bring us to a state of consciousness that unites our inner, spiritual life and our outer, physical life. This is messianic consciousness, for the essential function of Mashiach is to unite heavens and earth (on various planes, e.g., to unite the wisdom of Torah and the wisdom of science).
Eliahu Ba'al Shem, Yoel Ba'al Shem, and Adam Ba'al Shem were the leaders of the band of the hidden tzadikim, each in his generation. Then came the Ba'al Shem Tov who began his adult life as the leader of the hidden tzadikim but later was instructed from heaven to reveal himself and his teachings to the world. From that point on, his great disciples and their disciples, to the present day, all assumed the leadership of the Jewish community as revealed tzadikim. Inspired by Ba'al Shem Tov, they succeeded to unite the hidden dimension of their own souls, their inner life, with their revealed dimension, i.e., to unite within themselves heavens and earth, and thereby reveal to the world at large the essential goodness inherent in all of God's creation.
The ten generations from the Ba'al Shem Tov to our present generation correspond to the ten sefirot (the Divine channels of creation), above which are three hidden "heads of heads," corresponding to the three generations of Ba'alei Shem that preceded the Ba'al Shem Tov (this means that we are now the 13th generation from Eliahu Ba'al Shem).
The sum of the three hidden "heads of heads," Eliahu (אליהו, 52), Yoel (יואל, 47), Adam (אדם, 45), equals 144, = 122 (144 is also the 12th "love number," secularly referred to as "Fibonacci number"). Together with Yisroel (ישראל, 541), the fourth Ba'al Shem, the Ba'al Shem Tov, the full gematria, 685 (5 times 137 [the inverse of the fine structure consant], קבלה, Kabbalah) is the 19th inspirational number (following 613), i.e., 192 plus 182.
Eliahu Ba'al Shem (אליהו בעל שם, 494), Yoel Ba'al Shem (יואל בעל שם, 489), Adam Ba'al Shem (אדם בעל שם, 487), Yisroel Ba'al Shem Tov (ישראל בעל שם טוב, 1000, the secret of the 1000 lights given to Moses at Sinai) all together equal 2470 = 19 times 130 (5 times 26, God's essential Name, Havayah) = 5 times 494 (19 times 26), Eliahu Ba'al Shem, the origin of all (the unknowable head of simple faith in God)!