Now, more than at any time in the past, man's destiny is more subject to his own control and influence. This is true for many facets of civilisation, not the least of which is man's bioinorganic chemistry. It has been widely established that all metals are potentially harmful and yet many of these same metals? in trace amounts, are absolutely essential to our health, safety, and longevity [l] .
In order to assess our requirements for trace metals, to ensure adequate surveillance of the trace metal constituents of our foods, and to design ligand drugs to remove excesses of undesired metals, it is necessary to have a thorough knowledge of speciation. This is the key to understanding many of the important bio-inorganic mechanisms which occur in vivo. A realisation of this fact has given an impetus to develop new techniques for speciation analysis, and national and international bodies have been set up to examine all aspects of trace metals in viva.
Essentially, their tasks involve assessing (i) how the metals pass from soil into plants and animals and thence into man's diet, (ii) the imbalances which may well be associated with disease in man, and eventually, (iii) the restoration of trace metal balance by appropriate therapy. All facets of this trace metal food chain are examined in the following five lectures.