Though men's fashions generally change much more slowly than women's, men's styles in the '30s, '40s, and 50s did have distinct differences. The 40s can be divided into three distinct periods: pre-war, which differed little from the 30s; the war years, marked by War Production Board regulations and dwindling numbers of male civilians; and the post-war years, characterized by excessive use of fabric and exaggerated styles.

On September 3, 1939, England and France declared war on Germany for invading Poland, and refusing to withdraw troops. The United States officially entered World War II on December 8, 1941. On March 8, 1942, the US Government War Production Board issued regulation L - 85, which regulated every aspect of clothing and restricted the use of natural fibers. In particular, wool supplies for civilian use were cut from 204,000 to 136,000 tons in order to meet military requirements. All countries turned to the production of artificial fibers. Viscose and rayon (derived from wood pulp) were the most common. Unfortunately, however, they weren't a good substitute because they weren't very warm and had a tendency to shrink.

Stanley Marcus, the apparel consultant to the War Production Board, took the stand that it was the designer's patriotic duty to design fashions which would remain stylish through multiple seasons and use a minimum of fabric. Therefore, men's suits were made without vests, pocket flaps, and trousers lost their multiple pleats and cuffs.

There was one exception to the strict rationing of the early forties - the zoot suit. By no means was it sanctioned by the War Production Board - as a matter of fact, the zoot suits were thought of as contraband and illicit items during the War. The fashion was born during the early thirties in Harlem's nightclubs. It was an exaggerated look comprised of an oversized jacket, wide lapels and shoulders, with baggy low-crotched trousers that narrowed dramatically at the ankle. The zoot influence remained through the 1940s and men's coats were noticeably roomier as a result of it. Higher-waisted trousers were also due to the influence of the zoot suit.

The end of the war and rationing brought a dramatic change in fashion. After the war, most men, tired of uniforms and restrictions, preferred generously cut suits in pinstripe, herringbone, or glen plaid fabrics. Long coats and full-cut trousers were a sign of opulence and luxury, coming in a full spectrum of colors from garish to delicate hues. Jackets were very broad-shouldered with wide lapels and two or three buttons. These were worn with generously pleated and cuffed pants with deep patch pockets and slightly tapered ankles. These suits were everything wartime suits were not! After years of not being able to purchase vests, wearing a suit without one became the social norm, and remains so to this day.

One of the most extreme changes in postwar men's fashion was the adoption of the casual shirt. In 1946 and 1947, Hawaiian or Carisca shirts were first worn on the beaches in California and Florida. Made in bright colors, the shirts sported fruit, flowers, flames, women or marine flora. About this time, a man walking the streets of New York without a jacket, became a common sight.

Common tie styles included solid or red, blue, and white striped ties worn in Windsor knots. Ties were quite wide, fairly short, and loudly colored and patterned. Popular were wide tie clasps, heavy gold key chains, bold striped ties, big buttons, and the coordination of hair coloring and clothing.

Hair is short and natural, parted on the side. Mustaches remain on the older sophisticated. The hearty, "tough" look appears with the double-breasted darker suit and the hat brought down over the face.

In 1949, Esquire promoted a new look by labeling it "the bold look". Its characteristics were a loose fitting jacket with pronounced shoulders. Other style changes included single-breasted jackets with notched lapels and three buttons. Henceforth, peaked lapels were reserved for double-breasted jackets. These jackets also included a center vent.

The end of the decade saw American men home from the war and craving a new look, tired of uniforms. American designers left their mark on the world with sportswear. Europe now looked to the United States for trends in sportswear. For the first time in history, young men were setting fashion trends and the older men were following.

Men's casual fashions didn't change a whole lot during the 40s. Sport jackets and sweaters remained fashionable, and the loafer coat was made. This was a soft-tailored sport jacket with a shirt-like spread collar, patch pockets, and a two-tone look.