Here is bread, which strengthens man's heart, and therefore is called The Staff Of Life.
Bread is a key food - the key foodstuff for many cultures - made from baking (cooking) a mixture of flour (ground cereal) and water. It is probably the most common way of converting a cereal crop into something easier to eat. The most familiar bread worldwide is made from one form of wheat or the other but barley, ground peas and beans and maize have all played major roles as well - wherever the staple crop has been a cereal that cannot be easily cooked into something appetising, it will usually be ground and made into bread1. Primitive forms of bread made from pretty much any starchy material seem to be in evidence as far back as thirty millenia ago (~28,000 BC) but cereals become predominant around 8000 BC with the dawn of agriculture.
There is a lot more to the making of bread - the addition of salt, herbs and spices, for example and the inclusion of nuts, fruit and vegetables are all common, but probably the most significant refinement is the use of yeast. Yeast is added to the flour-water mixture to form a dough which is then allowed to sit in a warm environment so that that carbon dioxide produced by the yeast creates bubbles making the resulting bread softer and greater in volume. When the bread has 'risen' sufficiently it is then baked to cook it and to kill the yeast. The use of yeast and partial fermentation has a significant amount in common with the making of beer - and in early history the two could get pretty similar with primitive beers often being basically liquid bread. Pliny the Elder records the Gauls and Iberians as using the foam from beer in their breadmaking.
Modern baking can also use chemical additives such as baking soda to replace the yeast and speed up the rising process. The exact nature of the source grains, additives and baking process control which of the hundreds (at least) of different kinds of bread you end up with. Other differences may stem from the shaping of the bread, normally for cosmetic purposes.
Historically bread has often be socially stratified with the best and finest white bread (manchet in medieval Europe) commanding the higest prices and serving the finest tables, whilst coarser, darker breads made from poorer ingredients (possibly mixing or replacing the wheat with barley) fed the poor - how fresh your bread was could often be a function of status and income as well. In some times and places bread was also baked as food for dogs and horses - often mostly barley bread with a significant proportion of straw and pea or bean meal added.
One who makes bread for a living is known as a baker. In small, primitve or rural communities everyone will probably bake for themselves. How often a community bakes will likely be a function of wealth and developement - a poor, primitive community may only fire up the ovens once a week and bake enough bread for seven days (which may be pretty unpleasant come the next baking day). Eventually the volume of bread required may be more than the ovens can handle all at once (or people may decide that they can afford slightly fresher bread than this) and there will be another baking introduced. Eventually - and quite quickly in urban areas - the baking becomes daily and needs a professional to look after it. Hence the baker.
Culturally bread is extremely significant to those cultures that use it3 - because it is the staple food source of the culture it also represents life itself and becomes a metaphor for payment ("Breadwinner", "Putting bread on the table", "earning your crust") … if not the actual means itself (Grain-based local currency)… and significant in cultural and religious ceremonies (like the Christian Eucharist). The English word "lord" is derived from the Saxon for "giver of bread" and a companion is one with whom you eat bread. Productive land is most likely to be referred to as the "bread basket" of the region that it feeds. The list goes on. In cultures with a strong hospitality tradition, bread and salt were often the key indicators that forged the host-guest bond. It may also represent stability, continuity and mundanity - in The Lord's Prayer "Our daily bread" is seen to represent the day-to-day necessities of life and, again in the Eucharist it is coupled with wine to represent the totality of human need ("bread for your feasting, wine for your joy and worship to feed the soul").
The metaphorical mundanity and wholesomeness of bread were often seen to have mystical significance as well - bread in your pocket or wrapped in a child's swaddling clothes could provide protection from abduction by fairies and fresh bread was said to go stale in the presence of unwholesome magic (much as milk would curdle), which could make it a detector - or perhaps an absorber - of magical attack.
Bread may symbolise fertility, labour, peace or the element of earth - alternatively it may also represent the harmonious fusion of the four classical elements (grain from the earth, mixed with water and air and baked in fire) and thus life or mankind.