Glassmaking has been practiced for more than 4,000 years. Among the earliest known examples of glassmaking are ancient Egyptian beads with a glass coating. Around 1500 B.C. a method of making bottles and jars was developed in which a core made from sand and other materials was covered with softened glass. After the glass hardened, the core was scraped out. Blown glass was introduced shortly before the Christian Era, probably in the eastern Mediterranean region.

Glassmaking reached great excellence in ancient Rome. Some objects were transparent, but many were opaque. One Roman technique involved dipping a glass object into molten glass of another color. The coating, when cool, was partially carved away, leaving a cameolike design.

After the fall of Rome, the quality of glassmaking declined, and in many areas glassmaking ceased. Glassmaking continued in the Near East, where it already had a 2,000-year history. Islamic glassmakers perfected carving, enameling, and gilding techniques. Knowledge of glassmaking brought by returning Crusaders led to the revival of glassmaking in western Europe during the 11th and 12th centuries.

By the late 15th century, Venice had become the world's glassmaking center. Strong guilds were established and laws were passed that made spreading information about glassmaking an offense punishable by death. Nevertheless, the information was spread, and by the early 17th century, quality glass was being made throughout Europe. Tumblers, goblets, bottles, and other objects were made in great quantity. The glass used was soda-lime and potash-lime glass with various impurities that gave it different colors, usually green or brown. Glass of many other colors, as well as clear glass, was also produced.

About 1675, George Ravenscroft had produced the first vessels of lead glass, which later became known as crystal. This type of glassware had a much greater clarity and brilliance than the other types of glass manufactured at that time.

Flat glass was produced up until the 19th century by blowing. In one method, a blob of glass was gathered on a blowpipe and blown into a large hollow globe. The blowpipe was then detached from the glass, creating an opening in the globe. An iron rod called a pontil was then attached to the glass at a point opposite the opening, and the rod was spun to spread the glass into a disc up to about five feet (1.5 m) in diameter. Small, nearly flat panes could then be cut from near the outside of the disc.

Another method of flat-glass manufacture consisted of blowing a large cylinder of glass and then cutting the cylinder open and flattening it out to produce a flat sheet.

A twofold revolution in glassmaking methods took place after 1900. The industry became almost completely mechanized. Also, scientific knowledge of the physics and chemistry of glass made it possible to create special glasses for countless new purposes. Many of these developments were pioneered in the United States. Some of the landmarks were: the first fully automatic bottle machine (1903); the Colburn continuous method of drawing sheet glass (1904); quantity production of Pyrex heat-resistant glass (1915); laminated safety glass (1928); fiberglass (1931); and float glass (1959).

By the mid-1970's the float method had become one of the major methods of making flat glass. Research and development of new glasses, particularly glasses required for specific applications, is continuing.