My G-grandfather-in-law, Barnett Renovitch (spelled many ways) emigrated from Vilkaviskis, Lithuania to London in about 1880.  There were several other families from Vilkaviskis there at the time, the most distinguished being headed by Jacob Reinowitz, the Rabbi and Dayan.  In addition, there was Jacob's younger brother Chaim Renewich who was also a Rabbi and secretary to the London Chief Rabbi.  There were also some of Jacob's nieces and nephews living in London, children of Elias Reinowitz from Vilkaviskis.  These siblings (and also a known sister Esther) are said to be the children of a David Reinowitz. I have long wondered if our Renovitch family was related to the Reinowitz etc family.  JewishGen has a tax and voters list listing 10 entries of members of the Rajnowicz family in Vilkaviskis, including Iankel (Jacob), Eljasz (Elias), Chaim, and Pejsach (Pesach/Pizer, the father of Barnett) and a couple more.  The fact that Pesach is listed with the other known family members makes me think that he could be another brother - though it is also possible that he could be a cousin or more distant. 
The London obituaries for Jacob Reinowitz (d. 1893) and for his wife Esther (d. 1906) say that Jacob was from a long line of distinguished Rabbis. Unfortunately they are not more explicit. Family Search has a genealogy for Jacob Reinowitz going back many generations, with many of them Rabbis, to the 14th century.  I didn't click through all the lines, but the earliest ancestor I found was Chief Rabbi of Paris Matityahu Ashkenazi Treves III (1325-1387). As is obvious, in earlier generations this family was not limited to Lithuania.  
What could be the source for such extensive Rabbinical genealogies?  Is there a book or library somewhere that holds these? How reliable is it likely to be?
If you are a descendant of this family, I'd appreciate you getting in touch. My husband has a small DNA link with a descendant of Chaim Renewich and I'd like to check for more DNA links with known family members. But even if you don't want to DNA test, I'd just like to hear your family story.
Any help appreciated,
Jocelyn Keene
Pasadena, California

My Brin/Brown family from next door Vishtinetz/Wiestieniec/Wistitten/Vistytis  (a few miles from Vilkaviskis) and Edinburgh were rabbinical. One of the Browns/Brins married a Renovitsky, which seems rather similar to Renovitch.    

Jill Whitehead, Surrey, UK

See some of my research https://www.davidicdynasty.org/descendant-family-trees/
chaim Freedman

There are many books, mainly in Hebrew , with lengthy rabbinic family genealogies.
see some of my research at https://www.davidicdynasty.org/descendant-family-trees/
Chaim Freedman