Ancient people first began cooking

Ancient people first began cooking on open fires. The cooking fires were placed on the ground and later simple masonary construction were used to hold the wood and/or food. Simple ovens were used by the ancient Greeks for making bread and other baked goods. By the middle ages, taller brick & mortar hearths, often with chimneys were being built. The food to be cooked was often placed in metal cauldrons that were hung above the fire. The first written historical record of an oven being built, refers to an oven built in 1490, in Alsace, France. This oven was made entirely of brick and tile, including the flue. mprovements to Wood Burning Ovens

Inventors began making improvements to wood burning stoves primarily to contain the bothersome smoke that was being produced. Fire chambers were invented that contained the wood fire, and holes were built into the top of these chambers that cooking pots with flat bottoms could be placed directly upon replacing the cauldron. One masonary design of note, was the 1735 Castrol stove (aka stew stove) invented by French architect François Cuvilliés. It completely contained the fire, and had several opening covered by iron plates with holes.
Iron Stoves

Around 1728, cast iron ovens really began to be made in quantity. These first ovens of German design were called Five-plate or Jamb stoves.
Around 1800, Count Rumford (aka Benjamin Thompson) invented a working iron kitchen stove called the Rumford stove that was designed for very large working kitchens. The Rumford had one fire source that could heat several cooking pots, the heating level for each pot could be regulated individually. However, the Rumford stove was too large from the average kitchen and inventors continued to improve their designs.
One successful and compact cast iron design was Stewart's Oberlin iron stove, patented in the 1834. Cast iron stoves continued to evolve, with iron gratings added to the cooking holes, and added chimneys and connecting flue pipes.

Coal & Kerosene

Frans Wilhelm Lindqvist designed the first sootless kerosene oven.
Jordan Mott invented the first practical coal oven in 1833. Mott's oven was called the baseburner. The oven had ventilation to burn the coal efficiently. The coal oven was cylindrical and made of heavy cast iron with a hole in the top, which was then enclosed by an iron ring.

Gas

British inventor, James Sharp patented a gas oven in 1826, the first semi-successful gas oven to appear on the market. Gas ovens were found in most households by the 1920s with top burners and interior ovens. The evolution of gas stoves was delayed until gas lines that could furnish gas to households became common.
During the 1910s, gas stoves appeared with enamel coatings that made the stoves easier to clean. One important gas design of note was the AGA cooker invented in 1922 by Swedish Nobel prize winner Gustaf Dalén.

Electricity

It was not until the late 1920s and early 1930s that electric ovens began to compete with gas ovens, however, electric ovens were available as early as the 1890s. However, at that time, the technology and distribution of the electricity needed to power these early electric appliances still needed improvements.
Some historians credit, Canadian Thomas Ahearn with inventing the first electric oven in 1882. Thomas Ahearn and his business partner Warren Y. Soper owned the Chaudiere Electric Light and Power Company of Ottawa. However, the Ahearn oven was only put into service in 1892, in the Windsor Hotel of Ottawa. The Carpenter Electric Heating Manufacturing Company invented an electric oven in 1891. An electric stove was exhibited at the Chicago World's Fair in 1893. On June 30, 1896, William Hadaway was issued the first patent for an electric oven. In 1910, William Hadaway went on to design the first toaster made by Westinghouse, a horizontal combination toaster-cooker.

One major improvement in electric ovens was the invention of resistor heating coils, a familar design in ovens also seen in hotplates.

Microwaves

The microwave oven was a by-product of another technology. It was during a radar-related research project around 1946 that Dr. Percy Spencer, an engineer with the Raytheon Corporation, noticed something very unusual.