A core collection of diverse cutting-edge techniques for the generation, expression, optimization, and characterization of recombinant antibodies. Readily reproducible protocols for lead generation range from the cloning of human immunoglobulin genes to the selection and generation of human recombinant antibodies by humanization approaches, molecular display technologies and transgenic animals. Procedures are also described on restructuring antibody leads into monovalent, multivalent, and bispecific binding fragments for a wide variety of in vivo applications. State-of-the-art technologies are described for the characterization of antigen-binding affinity and specificity with novel applications in radioimmunotargeting, cancer immunotherapy, drug abuse, and proteomics.