Advances in Heterocyclic Chemistry, Volume 139, the latest release in this definitive series on the field of heterocyclic chemistry, combines descriptive synthetic chemistry and mechanistic insights to yield an understanding on how chemistry drives the preparation and useful properties of heterocyclic compounds. Topics in this new release include Application of the Fischer indole synthesis in medicinal chemistry, Oxindole Synthesis via C-H Activation Methods, Ring-Closing Metathesis in the Synthesis of Fused Indole Structures, Synthesis of fuller heterocycles, The Literature of Heterocyclic Chemistry, Part XX, 2020, and Heterocyclic Zwitterions Based on Coupled Polymethines.