The book “Cheshbon Hanefesh” (English: “Self Accounting“; “Nefesh” here translates merely as “Self“, not “Soul” anything!) is in the Mussarite’s toolkit (at least officially). Cheshbon Hanefesh got its peculiar importance because Rabbi Yisrael Salanter encouraged reprinting the work. (Not to be confused with his encouragement of issuing a new edition for sound-alike “Tikkun Middos Hanefesh” by Rabbi Shlomo ibn Gabirol.)
Who authored Cheshbon Hanefesh? Mendel Lefin in 1845 (תר”ה), a Maskil. Mendel Lefin belonged to the bad part of the early Haskala movement (indeed, some of the actors were malicious heretics, while others were not)!
Did Rabbi Salanter ever condemn the author, at least? No.
The 1988 preface by Rabbi Yitzchak Isaac Sher in a mention of the author adds “not to be confused with Yitzchak of Stanov” (the infamous Seforim forger). Not one word about the author’s genuine sins.
In “Chochma Bagoyim – Using Secular Methodology for Personal Development” Rabbi David Lapin (no familial relation) records an enlightening written give and take between himself and Rabbi Lawrence Keleman.
Rabbi Lapin writes:
“… the Mussar system based on the thirteen Midot of behavior, first articulated by the Cheshbon Hanefesh and then taught and popularized by Reb Yisrael Salanter, was in itself an adaptation from the work of Benjamin Franklin.
Their debate concerns the permissibility of using secular wisdom from Ben Franklin, all the while happily unaware of the questions raised by the Cheshbon Hanefesh’s own authorship. Find a decidedly similar analysis in the introduction to Rabbi Nosson Kamentsky’s “Making of a Godol“, by the way…
*Although maybe there is an insinuation in the title page’s credentials: חברו הרב החכם מוהר”ר מענדל במוהר”ר יהודה ליב זבראב איש סאטנאב. The skimpy, pedestrian rank of “Harav” is crossed with often loaded “Hechacham”, followed straight away by the generic “MoHRaR” acronym and origin (and won’t bless his memory, either).
(For more thorough information on Cheshbon Hanefesh, possibly relating to the above, check out these two essays.)