The topic search is entirely manual. The topic list is arranged hierarchically with the most general topics at the top level. Subsequent levels become progressively more specific. Each top-level topic is numbered. Lower-level topics under this same topic repeat the top-level number augmented by a new number separated from the next higher level by a period.
The topic list is intended to provide a framework in which database entries can be related to each other through similar subject matter and is meant to cover all the areas in which links between Mesopotamia and later civilizations may be found. The topic hierarchy is infinitely expandable, both at the top level and at all subsequent levels.
Using the topic grid
The Topic Grid is a table containing all of the top-level topics with a link to each. Subordinate topics are listed on a separate page for each top-level topic. To get to the list of topics for any top-level topic simply click on that topic in the Topic Grid.
Each topic sub-list contains all the topics to be found under the top-level topic. Each topic sub-list is organized according to the second-level topics, with each second-level topic treated as a branch of a tree. Each second-level topic has a link to every database entry that is associated with any subordinate-level topic. This is also true of all subordinate-level topics: the database entries assoicated with all lower-level topics will appear under every higher node in the tree. Thus 1.2 has a link to every entry associated with 1.2, 1.2.x, 1.2.x.y, 1.2.x.y.z, and so forth down to the bottommost level of that particular branch. Similarly, 1.2.x has links to all entries associated with 1.2.x, 1.2.x.y, etc.
The topic sub-list contains a hierarchical listing of all the topics in that branch of the tree whether or not associated with database entries. Because the number of topics is large (and will continue to grow as the database expands) the topic sub-list is initially presented to the user as a closed list. The user can then optionally open an individual second-level topic or open all the topics. Once any or all of the topics have been opened, all the topics can be closed in a single operation.
Opening the topic sub-list
The topic sub-list can be opened a topic at a time or all topics can be opened at once. The topic sub-list is initially presented to the user with all topics closed. When a topic is closed, the subordinate nodes in the branch that is headed by that topic can not be seen, but if the second-level topic is a live hypertext link, a number in parentheses following the topic indicates how many database entries are associated with topics in that branch of the tree. A list of these entries may be seen by clicking on the topic. However, this list may be long, and it may desireable to follow the branch downwards to eliminate unwanted entries.
Opening all the topics
To open all the topics in one operation, there is a clickable button at the top of the index page. Simply click this button and all the topics will be opened revealing the hierarchical structure. The button looks like this:
Closing all the topics
To close all the topics in one operation, there is a clickable button at the top of the index page. Simply click this button and all the topics will be closed and all the subordinate nodes will be hidden. The button looks like this:
Opening or closing individual topics
To open (or close) an individual topic, go the the topic on the page. In front of the topic there will be an arrow pointing to the right () or to the left (). Clicking on this arrow will open the topic if it is closed or close it if it is open. The status of other topics that may be open or closed will not be affected by this. Because of the organization of the topic sub-lists, if the top (second-level) node is not a live link, then there will be no live links anywhere in that branch. Opening a branch that does not have a live link at the top level will not lead to links to database entries.
Using the topic sub-list
Once a topic is open, the hierarchical structure of that branch of the topic list will be visible. A number in parentheses following individual topics indicates the number of database entries associated with that topic hierarchically. To display a list of the titles of database entries associated with the topic, simply click on the topic.
Navigating the topic sub-list
To the right of each topic you will find two arrows pointing up and down ( ) and a sign saying 'top' (). The upward-pointing arrow () will take you to the previous second-level topic in the index and the downward-pointing arrow () will take you to the next second-level topic in the index. Clicking on the sign saying 'top' () will take you to the top of the page. The arrows wrap around the list. Clicking on the "next" arrow at the last topic will take you to the first topic and clicking on the "previous" arrow at the first topic will take you to the last.