99. Reading on Shabbos
One is not allowed to read shtarei hedyoitois, mundane documents, on Shabbos. Chazal made a rule that one is not allowed to read anything written, any ksav, other than Torah literature, on Shabbos due to the concern that one may come to read shtarei hedyoitois, any of these documents that are forbidden to be read on Shabbos, or out of concern that one may forgetfully erase that which is written. This creates a very serious shaila as much of the material that people often read, such as newspapers, street signs, etc. can easily fall under this prohibition. One interesting discussion mentioned by poskim is that it is written in Shulchon Oruch that on Shabbos one is not allowed to read even captions under pictures. This brings about the question of whether a person who is looking at pictures of tzadikim (e.g. pictures of the Rebbe) is allowed to read the inscriptions underneath. There are a lot of reasons to be lenient in this regard. However, as a general principle, all other forms of written information which are not relevant to the Shabbos itself, should not be read on Shabbos. This applies to printed information as well.