In addition to the five [pleasures] that are forbidden on Tish’a B’Av, there are [other] prohibitions that are connected to the fact that Tish’a B’Av is a day of mourning. Just as a mourner is forbidden to learn Torah during the seven-day mourning period (shivah), one may not learn Torah on Tish’a B’Av, in order not to divert one’s attention from the mourning. Another reason one may not learn Torah during a period of mourning is that Torah study makes one happy, as it says, The commandments of the Lord are upright, rejoicing the heart (Tehillim 19:9). It is even forbidden to learn Torah in thought, because even that makes one happy. However, it is a mitzvah to learn sad sections of the Torah, those that deal with Israel’s suffering and the afflictions that man encounters, for these areas are appropriate for the mood of the day. One should not learn them in depth, though, because such study makes one happy. But if one thinks of a novel idea (a chiddush) while studying a matter superficially, he need not worry, because that is the nature of learning (A.H.Sh. 554:4). And if he comes up with a significant chiddush and is worried that he may forget it by the end of the fast, he may write it down concisely (see K.H.C. 554:110).
One is allowed to learn the following topics: In Tanach, one may study the chapters that describe the churban (destruction), which are found in the books of Melachim, Divrei HaYamim, and Megillat Eichah. One may also learn the prophecies of the churban, which cover most of the book of Yirmiyah, part of Yechezkel, and small portions of Yeshayah and T’rei Asar. However, one should not study the prophecies that predict the destruction of the evil heathens, because they are joyous prophecies from our perspective. It is permissible to study the book of Iyov, which deals with suffering, but one should not study the end of the book [which is joyous]. One may also study the sections of admonition and calamity in the Torah portions of BeChukotai, Ki Tavo, and Ha’azinu. [In all of these cases], one may learn the verses with commentary, in order to understand the simple meaning of the passage, but not in order to delve deeply into it.
Regarding the aggadic sections of the writings of Chazal: one may study the passages dealing with the churban in Tractate Gittin (55b-58a) and [most of] Midrash Eichah Rabbah, skipping the sections that deal with consolation. It is also permissible to study the third chapter of Tractate Mo’ed Kattan, which deals with the laws of mourning and excommunication, as well as the Gemara at the end of Tractate Ta’anit, which discusses the laws of Tish’a B’Av.
In terms of halachic topics: one may study the laws of the three weeks and Tish’a B’Av (Sh.A., O.C. 550-561), as well as the laws of mourning (Sh.A., Y.D. 334-403). If a rabbi receives an urgent question in an area of halachah that one is forbidden to study on Tish’a B’Av, he should answer it without explaining his reasoning (M.B. 554:5).
One may study mussar works [on Tish’a B’Av], even though they quote [biblical] verses and rabbinic statements, because their whole purpose is to awaken a person to repent for his sins. Therefore, the regular joy one feels when learning Torah does not exist here.
Ideally, one should be careful about these laws starting midday of the eve of Tish’a B’Av. But we already learned that one who feels that limiting his learning to these specific topics will curtail his learning should learn whatever his heart desires, until Tish’a B’Av begins (see Rama 553:2; M.B. 8; above 9.3).
One may not read exciting books or newspapers, or study other disciplines on Tish’a B’Av, so as not to divert one’s attention from mourning (A.H.Sh., Y.D. 384:9). It is, however, permissible, and even fitting, to read history books about the churban, the exile, and the hardships that have befallen the Jewish people.
The Acharonim debate whether the mitzvah of Torah study applies on Tish’a B’Av and the seven-day mourning period [for the death of a close relative]. The author of Sheivet Yehudah writes that there is no obligation [to learn during these times], while R. Chayim Palagi holds that one is obligated to study the sad sections [mentioned above]. See Yabi’a Omer, vol. 8, Y.D. 35 and Piskei Teshuvot 554:2, 3.
Regarding Torah learning and young children, see below, halachah 21.