The Gemara in Masechet Shabbat (149) establishes a number of restrictions on reading material on Shabbat, including a prohibition against reading words written underneath a picture of a painting. The Sages forbade reading these words as a safeguard against reading commercial documents and the like, which is clearly forbidden on Shabbat. Accordingly, somebody who sees paintings in a hotel or museum on Shabbat must not read the captions underneath the paintings.
Rabbi Moshe Halevi, in his work "Menuhat Ahava," Helek 1, page 236, cites authorities who allow reading on Shabbat the captions underneath pictures of Rabbis. Since there is a Mitzva involved in looking at pictures of distinguished Rabbis, as this could enhance one's Yir'at Shamayim (fear of God), it would be permitted to read the captions identifying the Rabbis, even on Shabbat. Nevertheless, Rabbi Moshe Halevi advises conducting oneself stringently in this regard, and refraining from reading even the captions underneath pictures of great Rabbis.
Halacha forbids proofreading material on Shabbat, as well. For example, an editor of a book or pamphlet may not review the material on Shabbat, even though he intends to make the corrections only after Shabbat, since he may forgetfully write or erase during Shabbat. Likewise, a Sofer (scribe) may not review a Sefer Torah on Shabbat, even though he of course plans to correct any mistakes only after Shabbat. (ibid)
It is forbidden to read advertisements on Shabbat, even if they pertain to Mitzva merchandise or services, such as advertisements for judaica, books of Torah or Arba Minim (four species). (See Menuhat Ahava, Helek 1, page 233.)
As we have seen, even reading the captions underneath pictures of Tzadikim might be forbidden on Shabbat. It should therefore go without saying that reading novels, science fiction, newspapers and other mundane material is forbidden on Shabbat. One's reading during Shabbat should be devoted exclusively to the study of Torah.
Summary: The following materials may not be read on Shabbat: captions underneath pictures or paintings, business-related documents, advertisements of any kind, materials requiring proofreading, newspapers and novels.
