In this book, the authors present topical research in the study of aldehydes. Topics discussed in this compilation include the synthesis and properties of intermediates in reactions of aldehydes with P(III) chlorides; synthesis of heterocyclic compounds by interaction of aldehydes with monoterpenoids; update on aliphatic aldehydes in lipid foods; inhibition of microbial biocatalysts by biomass-derived aldehydes and methods for engineering tolerance; co-oxidation processes promoted by N-hydroxyphthalimide/aldehyde systems; and the structure of gossypol condensation bis-product with 2-amino-4,6-dioxypyrimidine in acidic environment.