Nodah B'Yehuda & Kabbala - private & public view by Rabbi Dr. David Katz
The follow is an excerpt from Rabbi David Katz' doctoral dissertaion on the Nodah B'Yehuda. Rabbi Katz is a rav in Baltimore and is a very well respected talmid chachom as well as very knowledgable about many other things. The full dissertation can be downloaded here from the University of Maryland. The main point is that the Nodah B'Yehuda had a negative public attitude towards Kabbala but privately he had a strongly positive one. This also was true of Rav Yaakov Emden, Chasam Sofer and others. This duality was resulted from the concern for the followers of Shabtsai Tzvi and the Frankists as well as the well founded fear of the ignorant studying kabbala without a proper teacher or foundation.