What is Cold-Process Method in soap making?

This is the most popular method making soap at home, it is also the most complex.  

The age old method of cold process which involves the saponification of different oils and sodium hydroxide (lye). Through this process, the highly prized glycerine (by-product of saponification) which is highly moisturizing is mostly retained on the soap leaving your skin nourished and feeling soft, smooth and moisturized.

For cold process method, soaps need to be cured at least 4-6 weeks before use.  Curing allows most of the water within the soap bars to evaporate so that the soap is harder and milder on the skin.