Cereals are part of plants of Poaceae family, used to make flours. Since they provide more food energy than any type of crop, they are grown in greater quantities, so they are considered as staple crops. Emmer wheat was probably the most ancient type of cereal ever domesticated and cultivated by man.
The most common Cereals are barley, rice, wheat, maize (or corn), emmer, oat and rye. Sometimes also buckwheat is included, even if it is more a pseudocereal.
Cultivation of cereal crops is quite similar from species to species: they are annual plants, mostly, even if diveded into cool-season and warm-season cereals. Anyway, after harvesting, grains are the most used part. The whole grains, that is grains in their natural form (endosperm, germ and bran), they are a rich source not only of carbohydrates, but also of vitamins, minerals, fats, oils, and protein. Unfortunately, when refined, mostly the carbohydrates remain.
In cooking, they are so largely used that we can’t make a list of most common dishes. For example, here in Italy, among pasta and pizza and risottos and breakfast, we use them really a lot.
Fun fact: since a few years ago, a greater and greater deal of interest has been given to coeliac disease. So, a large amount of gluten-free Cereals have been re-introduced on the market, like buckwheat, quinoa, maize, rice, and amaranth.