The most formal, and most conservative, way for a gent to dress, is white tie and tails. The tail coat is pretty much what you will find in any tux shop or vintage clothing store. Essentially, you are dressing like the conductor of a symphony orchestra.

The properly dressed gent will wear a black coat, black trousers, a white evening vest and a white, winged collar. The evening vest is one that is cut low, and has lapels. A modern "cheater" is fine, as long as you don't let on that you are wearing one.

A cummerbund, with a tail coat, simply isn't done.

A white pocket handkerchief and white gloves complete the outfit. A gentleman who is dancing would be well advised to have two or more pairs.

To really cut a figure, if you are going about outdoors, this should be worn with a black wool cape, a black silk top hat, a white silk scarf, and a black cane. None of this is necessary, of course, if you are going to be indoors, since a Jazz Age gent would never wear a hat indoors.

While the Victorian gent had only tails as an evening option, the 20th Century brought gentlemen a set of new choices for evening wear. The 20th Century brought the Tuxedo, which was a formal version of the gentleman's suit coat.

A tuxedo is worn with a black bow tie, and can be single or double breasted. It is black. If it is single breasted, it should be worn with a black evening vest. A black cummerbund is acceptable for the 30s and later, but the vest is better. The tux is worn with the same black trousers you would wear with the tails.

The shirt must be white, and can have a winged collar or a simple falling collar.

The tuxedo is less formal that the tail coat. When the tux came along, it became necessary to specify how formal an event was going to be. If tail coats were required, the evening was "white tie". If tuxedos were acceptable, it was "black tie". At a black tie event, a gent with tails could wear a black tie with a black evening vest.

In the warmer months (Memorial Day to Labor Day is a good rule of thumb), gentlemen can substitute a white tuxedo cut "dinner jacket" for his tux jacket. This can be single breasted or double breasted, and worn with black trousers, a black tie, a white shirt, black shoes and a black evening vest. A black silk hanky makes a nice touch in the breast pocket.

A few things to avoid:
Ruffled shirts
Colors other than black or white
Single breasted coats without vest or cummerbund

I will talk about deviant fashions, like white tail coats and "mess jackets" in a future post.