Punctuation

Comma - Adjectives:

Use commas to separate coordinate adjectives that modify the same noun:

                         He had a big, round ball.

                         She wore a long, ruffled, orange skirt.

        NOTE: Coordinate adjectives can be interchanged without creating an 
                  awkward sentence.

Do not separate adjectives that are not coordinate:

                         The old brick house was demolished.
                                                -NOT-
                         The old, brick house was demolished.

        NOTE: Since "old" and "brick" are not interchangeable in this
                  sentence they are not coordinate. Thus, the comma separates
                  them needlessly in the second example. 

Comma - Appositives:

Use commas to enclose or separate appositives:

                         Phil, the big fat guy, squeezed into the 
                         front seat.

        NOTE: An appositive is a word or phrase that relabels a preceding noun.

Do not use commas to enclose or separate an appositive that has become part of a proper name:
                         Jimmy the Greek  

                         Alexander the Great

Comma - Clauses:

Use a comma to separate the parts of a compound sentence when a pause is needed for clarity and/or when the clauses are long:

                         Good cheese has been produced around
                         here for years, and I enjoy having fresh cheese 
                         available.

Do not use the comma to separate the parts of a short compound sentence:

                         The time is now and the need is great.               
                         
Do not use a comma to separate two verbs that share the same subject:

                         He came from way out west and quickly 
                         learned the eastern style. 

                         My boss always arrives early and stays late. 

Use commas to enclose or separate a nonrestrictive (nonessential) adjective clause:

                         His car, which is badly rusted, was stolen 
                         again.

                         The thief, who apparently likes wrecks, 
                         struck in the middle of the night.

Do not use commas to enclose or separate a restrictive (essential) adjective clause:

                         A car that is badly rusted and in need of  
                         paint will rarely be stolen.

                         People who live in glass houses shouldn't
                         throw stones.

Use a comma after a long introductory prepositional phrase or clause:

                         By the length of his beard and hair, we could
                         tell he had been at sea a long time.

                         Because he lacked both food and water, we 
                         wondered how he had survived so long.

Short introductory prepositional phrases or clauses are usually not separated by a comma:

                         By midweek we were finished.
                                                     
                         On Monday mornings the bank is open early.

                         When you finish please lock the door and 
                         leave the key under the mat.

Use a comma after introductory participial (verbal) phrases:

                         Finding nothing but white water between
                         ourselves and the shore, we argued about
                         what to do.

                         Having no other choice, we swam for our
                         lives. 
                                                      
Use commas to set off nonrestrictive (non–essential) participial phrases:                                                     

                         The Binkly and Hopper comedy team, soon 
                         to arrive in town for a weekend of shows, 
                         is a riot.

Do not use commas to enclose or separate a restrictive (essential) participial phrase:

                         Everyone planning to stay in town for the 
                         weekend should try to get tickets to one 
                         of the shows.

Use commas to enclose or separate descriptive phrases following the noun they modify:

                         Big John, strong as an ox, is a dangerous 
                         man.

Normally, a comma is used to separate a dependent clause from the main clause:

                         Unless telephone numbers are listed in
                         the directory, they can be very difficult
                         to find.

No comma is needed if the dependent clause is short, and it is clear where the main clause begins:

                         When we concentrate we can perform at 
                         our best.

However, if the main clause precedes the dependent clause, a comma is not needed unless the clause is clearly nonrestrictive:
                                                          
                         He comes here on Mondays because it 
                         is free spaghetti night.

                         He always eats at least three plates of
                         spaghetti, which is a lot of food for a
                         man of his small size.

Use a comma to set off words, phrases, or clauses if the meaning of the sentence would otherwise be unclear:

                         Unclear:    Underneath her attitude was friendly.

                         Better:      Underneath, her attitude was friendly.

                         Unclear:    Down the walk he came in his shorts 
                                          with his shirt tail flapping.

                         Better:      Down the walk he came, in his shorts,
                                          with his shirt tail flapping.

Use a comma to separate identical words in a sequence:

                         Whatever you do, do it well.

                         If it be so, so be it.

Comma-Compound Personal Pronouns:

Do not use commas to enclose or separate compound personal pronouns:

                         Louise herself picked up the tab.

Comma - Contrasting Words or Phrases:

Use commas to enclose or separate contrasting words or phrases:

                         Listening, not talking, is the way to
                         learn.
                                           
                         Typing is best performed when the 
                         typist uses all ten digits, not just
                         two or four.

Comma - Dates:

Use commas to enclose or separate dates:

                         The wedding was celebrated on March 15, 1989.

                         Since June 1, 1989, they have been living with the
                         parents of the groom.

Comma - Exclamations:

Use a comma to set off a light exclamation:

                         Oh my, that is good news.

Comma - Names, Personal Titles:

Use commas to separate the name of a person addressed from the rest of the sentence:

                         Quite frankly, Mr. Jones, the offer is
                         insultingly low.

                         Whenever you have troubles, Jim, you
                         should let us know.

Use a comma to separate inverted names in a reference or list:

                         Jones, John A.

Use commas to enclose or separate a title or degree from the name which it follows:
  
                         Phyllis Jenkins, Vice President 

Do not use commas to enclose or separate a title or degree from the name which it precedes:

                         Vice President Phyllis Jenkins

Comma - Numbers:

Use commas to separate large numbers into groups of three digits:

                         1,593,900,000

Use a comma to separate two consecutive numbers or words indicating numbers:

                         They had fifteen, one–hundred pound bags.

                         The rugby club now boasts 2,500, forty–year–old
                         members.

Comma - Omissions:

Use a comma to denote that a word or phrase has been omitted because it is obvious, or has already been used in the sentence, and need not be repeated for clarity:

                         Some men prefer blondes, others,
                         brunettes.

                         Anne and Sal quit smoking; Anne,
                         through sheer willpower; Sal, through
                         drugs and therapy.

        NOTE: The comma has replaced "prefer" in the first example and "quit
                  smoking" in the second.

Comma - Position or Location:

Use commas to enclose or separate a phrase denoting residence, position, or location:

                         Paul Thorn, 418 Front Street, was the 
                         best man.

                         John Alton, first place last year, is the
                         favorite again.

                         Seat fourteen, in the front row, is mine
                         for the season.

Comma - Questions:

Use a comma after a question that is not emphatic within a sentence if the sentence is not a direct quotation:

                         What's the use, we've lost.

But if the question is emphatic, insert a question mark in place of the comma:
                                                               
                         Who cares? is the question.

Comma - Quotations:

Use a comma to set off direct quotations in dialogue form:

                         "A lot of good that does me," she said.

                         He told the press, "First things first."

Do not use a comma to set off an indirect (paraphrased) quotation:

                         He told me that it couldn't be done.

Comma - Series:

Use commas to separate words or phrases in a series:

                         We dined upon roots, berries, tree bark,
                         wild grains and seeds, and the  
                         occasional slug or grub.

        NOTE: The comma preceding the conjunction and  before the final 
                  item in the series is optional.

Do not use commas when conjunctions connect all the items in a series:

                         We drank and frolicked and sang and 
                         howled till dawn.

Use commas before and after "etc." when it ends a series:

                         Baseball is an equipment–intensive
                         sport, one that requires bats, balls, 
                         bases, gloves, etc., to be played.

        NOTE: Since "etc." actually means "and so on," it always supplies its 
                  own conjunction.

Transitional Words & Phrases:

Use commas to enclose or separate a transitional word or phrase when a pause is needed to emphasize or clarify the meaning of the sentence:

                         Indeed, he had taken them all.
                                                
                         His was a rough life, it is true, one that was 
                         filled with many disappointments.

If the sentence is short and the meaning is clear, the transitional word or phrase need not be enclosed in or separated by commas:
                                                 
                         The shortstop therefore made the play.

                         The conductor nonetheless released the brake.

When the transitional word or phrase joins two independent clauses, it should be preceded by a semicolon and followed by a comma:

                         He could not afford to buy such an expensive
                         car; moreover, it will have depreciated
                         significantly before he makes the final 
                         payment.
                                                 
Use a comma when a sentence begins with "yes," " no," "why," or "well":

                         No, I will not say it.

                         Why, that is outrageous.

                         Well, you can say whatever you like about it.