Progress in Heterocyclic Chemistry (PHC) is an annual review series commissioned by the International Society of Heterocyclic Chemistry (ISHC). The volumes in the series contain both highlights of the previous year's literature on heterocyclic chemistry and articles on new developing topics of interest to heterocyclic chemists. The highlight chapters in Volume 10 are all written by leading researchers in their field and these chapters constitute a systematic survey of the important original material reported in the literature on heterocyclic chemistry in 1997. Additional articles in this volume also review "The Synthesis of Chlorins, Bacteriochlorins, Isobacteriochlorins" and "Higher Reduced Porphyrins and Heterocyclic ortho-Quinodimethanes". As with previous volumes in the series, Volume 10 will enable academic and industrial chemistry and advanced students to keep abreast of developments in heterocyclic chemistry in an effortless way.