What biographical information is known about Rabbi Yitzhak Izaik ben Yaakov haLevi Zorovitz, author of this sefer, among others. Apparently he was of a Chassidic background, but I wasn't able to find much out. What group of Chassidim? Who was his Rebbe? Was he himself a Rebbe?
On p 510 of The Yizkor Book For Premishlan there is an article (mainly stories) in Yiddish about Rabbi Yitzhak Izaik ben Yaakov haLevi who came from a village near Premishlan called Zorovitz. There it describes that he lived his life as an unknown figure whose scholarship and piety were not known to the people around him. They thought of him as an oddball.
Only after he passed away was his greatness recognized from the manuscripts that he left behind.
As you can see from Hebrewbooks.com, the Sefer Oisos de R'Yitzhak was published in 1801 in Zholkva. The first page seems to mention that he was the shochet in Zorovitz.