While each internet search engine will have its own search rules, the following general guidelines for Simple, Boolean, and Proximity searching will often prove useful.

Basic Difference between Search Types

1. Simple searches are good for casting the broadest possible net for a word or term. On common words, this may find a very large number of items. You may then wish to modify your search by doing an advanced search.
2. Boolean searches allow you to combine up to four search terms. You also have the option to look for the terms in the Same Page, Same Chapter, or Same Work.
3. Proximity searches look for the co-occurrence of search terms. This allows you to specify the spatial relationship between words you are looking for. You can look for words following each other or near each other.

Simple Searches

A simple search is quick and easy. Enter a name, word or phrase (phrases would be a so-called string, enclosed within quotation marks) and the search engine will look for it in every page it has indexed.

Boolean Searches

Boolean searching allows one to combine up to four search terms. For example, submitting a query for iron will result in a full-text search for all works in the database in which the term occurs. If the term curtain is added with a Boolean operator, then the search would be limited to the designated relationship between iron and curtain. You can broaden or narrow your Boolean search by using the options for:

• Same Page, which looks for your terms when they all appear on the same page.
• Same Chapter, which looks for your terms when they all occur in a set chapter.
• Same Work, which looks for the terms anywhere in the work.

Boolean Operators (And, Or, Not)

The Boolean operators are And, Or, and Not. Boolean expressions are operated on from left to right. This means you will need to take some care in formulating your search.

For example, you may wish to find a text that includes the word frontier And either the words pioneer Or Indian. Your search should be formulated as "pioneer Or Indian And frontier".

Since the search works from left to right, the search will first look for the set of texts that contains either pioneer Or Indian. The search then will look within the retrieved set of texts for instances where the word frontier also is found. The result is the combination of the text sets which have been found.

If you had formulated your search as "frontier And pioneer Or Indian" you would have received very different results. Why? Remember that the search works from left to right. The search would have first looked for the set of texts that contains both the words frontier And pioneer. Next it would have looked for the texts that contain the word Indian. Then it would combine those two sets of results and eliminate the duplicates to produce the final result. This means that you would have a whole set of texts that contained the word Indian, but not frontier And pioneer.

Think of the Boolean format as a bracketed mathematical expression:

            [( a * b ) * c ] * d

The search operates first on the smallest innermost bracket, second on the next largest bracket and the results of the first bracket, and third on the outermost term and the results of the second bracket.

Proximity Searches

A proximity search looks for the co-occurrence of two or three search terms. You can set search parameters by:

• Looking for words or phrases within 40, 80, or 120 characters.
• Finding instances where a term is either Followed By or Near another.
• Looking for places where words are Not Followed By or Not Near other words.

For example, if you want to find texts in which the terms Mississippi River and steamboat appear relatively Near each other, search for those terms within 40 characters of one another. This may help you find articles about "steamboat traffic on the Mississippi River."

To find those terms only when one follows another, select the Followed By proximity operator. "Mississippi River Followed By steamboat" may help you locate articles specifically on Mississippi River steamboats. If you want to find all instances where a term is not followed by another closely associated term, you may use the Not Followed By or Not Near operators. So if you were only interested in steamboats not directly related to the Mississippi River (maybe you are interested in steamboat traffic on the Missouri or Ohio rivers), a search for "steamboat Not Near Mississippi River" would find texts where steamboat is not connected with Mississippi River.