I was wondering if you would be able to answer whether there might be any halachic problems involved with copying the format/structure of an author’s published book?…

There is a Jewish author who has published and sells what appears to be an original type of book. As far as I am aware, this author has created a new format/genre of book. The author’s book is frum-themed, consists of frum content, and is marketed towards the frum community. I like the format & structure of the book and am considering making a secular book of the same format and marketing it towards the secular, non-Jewish community.

I wanted to ask if there might be any halachic issues involved with copying the format of someone else’s book – or – if as long as all of the books’ themes and content are being changed if no issues would exist?

The halachot of copyright are sometimes complex since there is very little premise for them in the gemara, rishonim, or even the shulchan aruch. The discussion on the matter began in the mid-1600s with regards to copyrights on books, and whether an author or printer could prevent someone else from printing their book. In recent years, the discussion has focused on the idea of copying songs, computer programs, and the like.

See the following links for a general overview of the halachot of copyright: TorahLive, Halachapedia

There are several prohibitions to discuss in regards to copyright: The first is the problem of making a profit at someone else’s loss and taking away someone else’s business (השגת גבול). In addition, if we consider it possible to have ownership on something intellectual, then there could be a problem of stealing this intellectual property (גזל). All this would depend on how closely one is copying the original book, if they are marketing it to the same audience, and to what extent the original book is truly unique and no others exist. One should consult a Rabbi with the specific details of the situation to determine the halacha.

Also, we are bound to the civil copyright laws by dina demalchuta dina (דינא דמלכותא דינא). Therefore, in every case, one must determine what the copyright laws are in regards to that case.

All the best!