Q. Does one make a siyum on a sefer of nach?

A. Pnay Yehoshua (Brochos 17a) commenting on Rabbi Yochanan’s custom after ending Sefer Iyov, mentions that you should celebrate a siyum at the conclusion of the learning of a complete sefer of Neviim or Kesuvim. So too is the opinion of Minchas Pitim (Y.D. 246,26) and Piskey Teshuvo (1, 194 in the notes) quoting the Avney Nezer’s tradition.

Haelef Lecha Shlomo (386) rules that you can perform a siyum even on a short Novi with few chapters, and it would be considered a seudas mitzvah as long as it was concluded by happenstance and not planed (as to eat meat in the nine days). A similar opinion is to be found in Igrois Moishe (O.H.1, 57 and O.H. 2,12) where he adds that the learning should be truthful and with some depth.

It is of interest that Mishne Halochos (1, 451) opines that finishing any of the great and accepted seforim of Musar, such as the Mesilas Yeshorim is reason for a siyum, other Poskimm disagree (Rivevos Ephraim O.H. 189).

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a