These new volumes of Methods in Enzymology (554 and 555) on Hydrogen Sulfide Signaling continue the legacy established by previous volumes on another gasotransmitter, nitric oxide (Methods in Enzymology volumes 359, 396, 440, and 441), with quality chapters authored by leaders in the field of hydrogen sulfide research. These volumes of Methods in Enzymology were designed as a compendium for hydrogen sulfide detection methods, the pharmacological activity of hydrogen sulfide donors, the redox biochemistry of hydrogen sulfide and its metabolism in mammalian tissues, the mechanisms inherent in hydrogen sulfide cell signaling and transcriptional pathways, and cell signaling in specific systems, such as cardiovascular and nervous system as well as its function in inflammatory responses. Two chapters are also devoted to hydrogen sulfide in plants and a newcomer, molecular hydrogen, its function as a novel antioxidant.Continues the legacy of this premier serial with quality chapters on hydrogen sulfide research authored by leaders in the field Covers conventional and new hydrogen sulfide detection methodsCovers the pharmacological activity of hydrogen sulfide donorsContains chapters on important topics on hydrogen sulfide modulation of cell signaling and transcriptional pathways, and the role of hydrogen sulfide in the cardiovascular and nervous systems and in inflammation.