A precious little book, cheap, easy to read, where all it is imperative to know about magnesium if you want to find good health (or keep), is given with many details. Moreover, the magnesium deficiencies are common and cause many diseases, it is good to know that it is necessary to take a little each day. For example, in the case of osteoporosis, if there is a lack of magnesium, calcium does not bind to! (You also do not lack vitamin D, potassium and phosphorus). In conclusion, the infant to the old man, magnesium chloride is perfectly sovereign "its safety and immunostimulant action makes it a real panacea, usable in all circumstances, from the mildest to the most serious." Just a clarification: buy preferably Nigari, mentioned in the book (that is a salt that contains 80% magnesium chloride NATURAL) rather than the bags sold in pharmacies and magnesium containing synthesized. Personally this formula caused me pain in the kidneys and stayed for years without daring to take until I discovered Nigar! In addition it is cheaper!