Chemical Tools for Imaging, Manipulating, and Tracking Biological Systems: Diverse Methods for Optical Imaging and Conjugation, Volume 639, the latest release in the Methods in Enzymology series, continues the legacy of this premier serial with quality chapters authored by leaders in the field. Chapters in this new release include Fluorogenic detection of protein aggregates in live cells using the AggTag method, Synthesis and Application of Ratiometric Probes for Hydrogen Peroxide Detection, Chemical Tools for Multicolor Protein FRET with Tryptophan, Fluorescing Isofunctional Ribonucleosides for Adenosine Deaminase Activity and Inhibition, Temporal profiling establishes a dynamic S-palmitoylation cycle, Solvation-guided design of fluorescent probes for discrimination of amyloids, and much more.