Sign up for Weekday J and get the latest on what's happening in the Jewish Bay Area.

Toward the end of his latest book, Rabbi Martin Samuel Cohen professes his love of studying the Mishnah.

No kidding.

A person would have to love the Mishnah in order to write a 240-page book about one of its most obscure parts — one that deals with a topic that has little impact on people today: ritual impurity.

That’s precisely what Cohen has done in his new book, “The Boy on the Door on the Ox: An Unusual Spiritual Journey Through the Strangest Jewish Texts.”

The tome dissects Tohorot (cleanliness), which is one of the six major sections of the Mishnah, a written compilation of oral teachings by the sages from the 4th century B.C.E. to the 2nd century C.E.

Cohen’s life and career is all over the physical and literary map. He has lived and worked in Germany, Canada, New York and California. He has published four novels, four books of essays, a translation of Psalms, and a prayer book for his current congregation, Shelter Rock Jewish Center on Long Island, N.Y.

That’s all well and good, but what’s not good is that his latest book is also all over the map. It varies from reasonably simple and lucid to verbose and incomprehensible. Cohen makes his points with varying degrees of clarity and sentence length. On several occasions, he admits that the material is complex and difficult to follow, but urges the reader to keep at it.

Rather than explain the details of the complex laws of Tohorot, Cohen’s reads them metaphorically. Readers are taken on a journey through his fantasies and his reminiscences with a psychopomp, a person who guides the human soul’s search for God.

One question is about a boy at the perimeter of a cemetery. The issue: If the boy picks lilies from the cemetery, is he considered spiritually impure because of the presence of human corpses? In other words, is the boy “in contact” with a corpse?  

A seemingly simple question, but the answer, according to Cohen, defies simplicity.

Cohen addresses this issue in several ways: private space vs. public space present with others; the likelihood or doubtfulness of contamination; and the ease of carrying out the investigation.

Unfortunately, Cohen never actually answers the question. Instead, he tells readers that the boy in the cemetery was but a vehicle to teach the concept by example instead of lecturing.

“I realize that this must all seem very obscure to the uninitiated reader,” writes Cohen, in a fit of clarity. He then implores the reader to stick with him.

If the reader does, there are several other riddles to decipher — such as a boy on a door on an ox, and an ape acting as a valet. There are also personal travel vignettes to wade through — such as writing in a seedy motel in Spokane. All this material is supposedly designed to illuminate the most obscure points of the Mishnah.

As the reader plows though Cohen’s discourse, it becomes evident that his book is not for the uninitiated. To obtain the proper background, readers may wish to first pick up a more elementary text, such as something from the Artscroll Mishnah series.

“The Boy on the Door on the Ox: An Unusual Spiritual Journey Through the Strangest Jewish Texts” by Martin Samuel Cohen (240 pages, Aviv Press, $17.95)