Prof Walsh was on the faculty of MIT and Harvard Medical School and is now affiliated with the ChEM-H Institute at Stanford University. Yi Tang is a professor of Chemical and Biochemical Engineering, and Chemistry at UCLA. Between them they have published more than 300 research papers on the biosynthesis of the major classes of natural products. Their research groups have deciphered chemical principles and novel enzymes for assembly of polyketides, nonribosomal peptides and posttranslationally modified nascent proteins, oxygenated isoprene scaffolds, peptidyl nucleosides, and fungal alkaloids. Through sequencing of fungal genomes to identify novel biosynthetic gene clusters, heterologous expression in engineered yeast cells, overproduction, isolation and structural assignment, they have identified genes, encoded enzymes, and the structure of novel secondary metabolites in several natural product classes. This broad set of research experience and expertise makes them an ideal pair of authors for Natural Product Biosynthesis: Chemical Logic and Enzymatic Machinery.