Who said flour is flour?

Flour

Most cookies recipes use plain(all purpose) flour, it has low gluten content, resulting in a crumbly texture. 

The grains are processed with chlorine to make the flour whiter(It is unhealthy, no good). You can buy unbleached flour, which has a greyish colour. All flour must be sift before use, for better result.

Self-Raising flour

•  This flour contains raising agents that make cookies spread and rise, giving them a lighter texture.
• if you run out of self-raising flour, you can substitute plain flour, adding 5ml/1 tsp baking powder to each 115g/1 cup of plain flour. 
• SRF should not be kept for longer than 3 months because raising agents gradually deteriorate.

Wholemeal Flour

•  Milled from the entire wheat kernel and contains all the nutrients and flavour of wheat. It is coarser than white flour, giving heavier result. It absorbs liquid than white flour so recipes should be adjusted if wholemeal flour is used.
• Brown (wheatmeal) flour contains only 80-90% of the bran and wheat germ and has finer texture and milder taste

Non-wheat flours

Potato flour/starch

• This fine powder is made from potato starch and can be mixed with wheat flour to give a lighter texture to cookies

Chestnut Flour

• This light brown nutty flavoured flour is made from ground chestnuts and is often sold in italian delicatessens 

Cornmeal

• also known as polenta or maizemeal,this is bright yellow and coarse or medium ground

Cornflour/cornstarch

• This fine white powder is made from the middle of the maize kernel. It is often used in piped cookie mixtures to give a smooth texture.

Soya flour

• Made from soya beans, this has a distinctive nutty flavour. It has a high protein content. Medium- and low-fat varieties are available

Rice Flour

• This is made by finely grinding polished white rice and it used in many cookie recipes, to give a short, slightly crumbly texture. 

Gluten-Free Baking

Some people are allergic or intolerant to the protein gluten, which found in wheat and rye. Specially produced gluten-free and wheat-free flour mixtures can be used for baking, as can any of the naturally gluten-free flours such as cornmeal, potato flour, rice flour and soya flour.

Ref: The cookie Book by Catherine Atkinson and others