The full work is entitled "Beit Israel" meaning "House of Israel." Falk gives two explanations for the name (based on a common Biblical expression):
It is subdivided into two parts. The most important are:
Rabbi Joshua Falk (ben Alexander Katz).
Falk studied with the two most prominent Polish rabbis of the previous generation, Rabbi Solomon Luria and Rabbi Moses Isserles. Rabbi Falk spent his early life composing extensive analytical commentaries on the Talmud, which were later lost in a fire. He then turned his skills to the careful analysis of practical issues of Jewish observance, focusing on Rabbi Joseph Karo's "Beit Yosef" and "Shulhan Arukh."
Rabbi Falk was opposed to the reliance on law codes to the exclusion of studying the original sources. Towards this end he composed a series of commentaries on the most influential codes of his day, Rabbi Jacob ben Asher's Tur and Rabbi Karo's Shulhan 'Arukh.
Lvov (Lemberg), Poland
Whereas the Perishah is intended to clarify the rulings of the Tur, largely by tracing them to their sources in the Talmud and medieval codes, the Derishah is devoted to extensive analysis and comparison of the various interpretations and decisions proposed by various Talmudic authorities.
In his glosses to the Darkhei Moshe, Falk also cites recent decisions, largely from the responsa literature.
References to the Perishah and the Derishah are indicated, respectively, by means of small Hebrew letters in square or round brackets at the appropriate places in the text.