Unless you live in the area that grows kidney beans, you won't find them fresh but will have to settle for dried or canned forms. They are always eaten shelled and cooked. Lentils have been cultivated since ancient times, originating in central asia and forming the staple diet of the poor for many centurie. Ancient Rome imported whole shiploads from Egypt. Lentils are particularly good for children,anaemics and nursing and expected mothers, provided that there is no history of digestive problems.
Butter beans are a variety of Lima beans, grown in the southern United States.
Its more commonly used to grow bean sprouts. Mung beans are widely used in both China and India. They need no presoaking and when cooked have a tender texture and a slightly sweet flavour. Dried mung beans are ground into flour, which is used to make noodles in China and a variety of dishes in India. Navy beans require lengthy, slow cooking.