A. History books and novels:[1]

Similarly [history] books of wars (and the history of gentile kings) and parables and metaphors regarding mundane talk, such as the book Emanuel, and it goes without saying books of romance are forbidden to be read on Shabbos. Even to read them in one’s mind without verbalization [is forbidden], due to a decree against [coming to read] laymen documents.

During the week:  Furthermore, even during the week it is forbidden to be read [the above books] due to “ Moshav Leitzim/A setting of scoffers”, even if they are written in Hebrew.[2]Regarding books of romance there is an additional prohibition even if they are written in Hebrew, as one entices the evil inclination on himself, and those which compiled it and those which copied them ,and it goes without saying those which published them are included within those which cause the public to sin.

Ethical history books:  However those history books which bring out ethics and fear of heaven, such as the book of Josephus and the like, are permitted to be read even on Shabbos even if they are written in a foreign language [not Hebrew]. (Nevertheless it is not proper for people to spend much time reading them.)

B. Books of wisdoms, such as Medical books and the like:[3]

Some opinions say that it is forbidden to study [any book] on Shabbos and Yom Tov with exception to [books with] words of Torah and fear of heaven. Even books of wisdoms are forbidden [to study]. The reason for this is because  any book which does not have a remnant of holiness one is decree against [reading it] due to laypersons documents [which one may come to read].

Are these books Muktzah: According to this even to move these books is forbidden.

Other Opinions: There are those which permit [to read] all books of wisdom and books of medicine being that matters of wisdom will not be confused[4] with a laypersons document  and [thus] one is not to decree on this [type of writing] due to the other [type of writing].

The final ruling: The custom is to be lenient [like the second opinion].

Summary:

History books and novels:[5] Books of history and novels which do not contain themes involving morals and fear of heaven are forbidden to be read on Shabbos, even in one’s mind without verbalization, due to Mimtzo Cheftzecha. Furthermore, even during the week they are forbidden to be read due to Moshav Leitzim. Those history books and novels which do contain morale messages are permitted to be read on Shabbos

Medical books and other books of wisdom:[6] The custom is to allow reading books of wisdom and medicine on Shabbos.

General Summary on Books:

In general all non-Torah related books may not be read on Shabbos, unless they contain a moral message, or [according to our custom it is also allowed if they] are books of wisdom, such as healing and science and the like.

Q&A

May one read a book on Shabbos for the purpose of editing it after Shabbos?[7]

It is forbidden to read any book for the purpose of editing it after Shabbos[8].

May one read from the manuscript of a Sefer[9] which is meant for editing?

If it is designated only for editing and not learning: It is permitted to be read such a book on Shabbos for learning purposes[10], although for editing purposes it is forbidden to read it[11].[12] However there are some Poskim[13] which are stringent and rule that one should not read such manuscripts at all on Shabbos. [According to all] this manuscript is considered Muktzah Machmas Issur on Shabbos as it is designated only for writing on.[14]

If it is designated for both learning and editing:[15] Then it is not Muktzah at all. Although it is forbidden to read it for editing purposes.

May one read a Torah book on Shabbos for the purpose of writing about it after Shabbos, as is common with Chidushei Torah, or homework of Limudei Kodesh?

Some Poskim[16] rule that doing so is permitted[17]. However other Poskim[18] have written that one is to refrain from doing so. 

On Shabbos may one prepare next week’s Shabbos Torah reading?[19]

Yes.[20]

May one make a marking on a book in order to remember a place that needs correction, or the page that he is on?

It is forbidden to make an indentation on the book due to the writing prohibition.[21] However [according to some opinions[22]] one may bend the corner of a page as a reminder of where he is holding or as a sign that it needs correction. [23] See “The laws of Writing and Erasing on Shabbos” for the full details of this subject!