To those involved in the heterocyclic chemistry field, the need for a focus on 5-aminopyrazoles is apparent. This volume is intended to meet that need since the biological and medicinal activities of 5-aminopyrazoles have prompted enormous research aimed at developing synthetic routes to these ring systems. A search of the literature revealed large number of 5-aminopyrazole ring systems that fit this criteria. Such a fact may not be surprising for those who are interested in the chemistry of this class of compounds as, of course, there are theoretical and practical reasons for this interest. 5-Aminopyrazoles became of recent importance due to the reported anti-inflammatory and antipyretic properties of many of these derivatives. Moreover, in recent years, these derivatives have extensively utilized as intermediates for synthesis of fused pyrazoles of potential biological activity. The chemistry of 5-aminopyrazoles have been reviewed in two books which were published in 1964 and in 1967. The extensive literature that has been published since both books appeared made it mandatory to update knowledge in this area.