Analytical techniques. Microscopy. Single molecule techniques. Preparation of cells and tissues for microscopy. Principles of optical spectroscopy.Photometry. Fluorimetry. Chemiluminescence.Electrophoresis.Immunological methods.Isotope techniques -- Purification of proteins.Homogenisation and fractionisation of cells and tissues.Isolation of organelles. Precipitation methods.Chromatography. Membrane proteins. Determination of protein concentration.Cell culture -- Protein modification and inactivation. General technical remarks. Amine-reactive reagents. Thiol- and disulphide reactive reagents. Reagents for other groups. Cross-linkers.Detection methods. Spontaneous reactions in proteins -- Protein size and shape. Centrifugation.Osmotic pressure. Diffusion.Viscosity.Non-resonant interactions with electromagnetic waves -- Protein structure. Protein sequencing.Synthesis of peptides. Protein secondary structure. Structure of protein-ligand complexes. 3D-structures. Folding and unfolding of proteins -- Enzyme kinetics. Steady-state kinetics. Leaving the steady state: Analysis of progress curves.Reaction velocities. Isotope effects. Isotope exchange -- Protein-ligand interactions. General conditions for interpretable results. Binding equations.Methods to measure binding equilibria. Temperature effects on binding equilibrium and reaction rate -- Industrial enzymology. Industrial enzyme use.Immobilised enzymes -- Special statistics.Quality control. Testing whether or not a model fits the data -- Appendix. List of symbols.Greek alphabet. Properties of electrophoretic buffers. Bond properties. Acronyms. Undergraduate biochemistry courses cover what proteins do, as enzymes, receptors, hormones, motors or structural components. The much more interesting question is how can proteins achieve all these functions? Presented here is an overview of the methods used in such projects, their possible applications, and their limitations. Focusing on the biophysical chemistry of proteins, the text is accessible to those with a general background in chemistry, physics and mathematics, though a good understanding of protein structure and enzymology is required. The text may be used in courses of protein science, by students embarking on master- or PhD-thesis work in this area or by professionals who need a quick reminder about the essentials of a method.