PARENTHESES

What's the difference between parentheses and brackets?

Parentheses and brackets are similar in that they both enclose explanatory words and phrases or other incidental information. Brackets are generally used within parentheses or with quoted material:

Dextrose (usually sold in the form of fine, white granules

[grains] at specialty markets) is produced commercially by

putting starch in water mixed with dilute hydrochloric acid. 

John's reply stated: "I considered it my duty to inform my

supervisor [Fred Walters] of the discrepancy." 

Aren't parentheses similar to commas and dashes? Does some order of preference exist?

Commas, dashes, and parentheses are similar in that all may be used to enclose explanatory ideas and incidental information. However, each carries its own degree of emphasis. Commas are less emphatic than parentheses, while dashes are more emphatic. Note the differences in emphasis in each of the following:

All sorts of subtle advantages become available-after a

person's self-image has been altered to those who would

exploit that new image. 

All sorts of subtle advantages become available, after a

person's self-image has been altered, to those who would

exploit that new image. 

All sorts of subtle advantages become available (after a

person's self-image has been altered) to those who would

exploit that new image. 

All sorts of subtle advantages become available after a

person's self-image has been altered--to those who would

exploit that new image. 

When a sentence ends with a parenthesis, where is the period placed?

If only a part of the sentence is enclosed by the parentheses, the period is placed outside the closing parenthesis:

Rosenthal used the topic in a book (subscribing to the

city-caused apathy theory). 

Inconsistency is commonly thought to be an undesirable

personality trait (Brooks and Revnes, 1979). 

If the entire sentence is enclosed in parentheses, the period is placed inside the closing parenthesis:

(News stories began appearing in which various

kinds of public apathy were described.) 

(See appendix 4 for detailed data analyses.)