The nitrogen-containing ring structures are at the hub of metabolism and include ATP, nucleic acids, many coenzymes, metabolic regulators and integrators such as adenosine and GTP, signalling compounds such as cyclic nucleotides and plant cytokinins and biochemically functional pigmets of which haemoglobin, the cyhromes and chlorophyll are examples. This important book collates and integrates current knowledge of all the biologically important N-heterocyclic compounds, covering the relationship between their chemical structures and physiological functions within this key group of compounds. Few biochemical reaction sequences do not involve one of these compounds as a substrate, product or coenzyme and a full understanding of the interrelationship between their structure and function is vital for all those woorking in the field of biochemistry. Professor Eric Brown who has a huge wealth of experience in teaching and research on these compounds has written a very comprehensible and thorough book which will be of great value for advanced students and researchers in biochemistry and those at the interfacing subject areas of chemistry, biology and pharmacology including all those employed in researching biological function within pharmaceutical companies.