Descriptive Books are very large, leatherbound volumes which contain hundreds if not thousands of pages of special paper used for the Writing process. When a descriptive Book is blank, it is called a "kor'nea" or "blank book." Filled, these Books contain an immensely precise and detailed description of the Age the Writer wants to link to. These descriptions are made using a special script called the "gahro-hevtee," or "great words." To link to the Age, each Book contains a linking panel, usually located on the first right-hand page for convenience, but which could be placed anywhere in the Book.
Linking Books are used to return from the Age a person linked to. These Books are much smaller, containing only several dozen pages, and are also leatherbound. Linking Books always link to the location where they were written, but do not have a set requirement for what text they should contain. Gehn, in the Book of Atrus, states that the Linking Book must contain key phrases from the Book it is to be used with, but RAWA says that this is not true, and that you can write anything in the Book (including "where are the donuts," it would seem), and it will continue to work normally.
Often the D'ni would use Linking Books as stand-ins for Descriptive Books, because Linking Books are very portable and replaceable, while Descriptive Books are not.
Trap Books were an artistic invention by Cyan Worlds that are not officially part of the D'ni canon. Please see RAWA's letter to the Lyst about why Trap Books do not exist outside of Myst and Riven for more information.
Prison Ages are simply Ages with no way of returning (no Linking Book), or Ages where use of the Linking Book is restricted. Prison Ages were used by the D'ni to confine criminals of law, so as to remove them from the society in general.
Although the details are presently sketchy, it seems that the D'ni considered "Death Ages" to be separate from Prison Ages, implying that the explicit purpose of the Age was to kill its traveler instantly. There are several references to Death Ages in the Journals of the Kings drafted by the DRC, but perhaps the only other currently-documented occurrence of a Death Age in D'ni history is Aitrus' alteration of the Age of Ederat to stop A'Gaeris after the Fall of D'ni.
Relto is a unique Age in the history of the Art. Yeesha grants an instance of the Age to each explorer, and the Book which takes them there is capable of following them through the link. According to RAWA, Yeesha's abilities also enable her to specify an exact "instance" of the Age using the Linking Books she hands out, effectively accessing Relto across innumerable dimensions without having to re-write the Descriptive Book each time. No other D'ni writer has ever been able to accomplish these feats.
Modifying a Descriptive Book
This is covered more completely in Descriptive Book Modification.
Destroying a Book
If a Linking Book to an Age were to be destroyed, the link between the Age and the Descriptive Book would remain unharmed; only the Linking Book's link would be destroyed. If, however, the Descriptive Book of an Age were damaged or destroyed, the link to the Age would be destroyed, and the Linking Books which link to that Age would also cease to function.