Book excerpt: This detailed volume explores advances in vector design, DNA delivery, cell cultivation, host cell engineering, and bioprocess optimization within the study of recombinant protein expression in mammalian cells. The majority of the protocols employ either Chinese hamster ovary cells (CHO) or human embryonic kidney 293 cells (HEK293), the workhorses of the field, as the production host; however, the methods can be adapted to other mammalian hosts under the appropriate cell-specific conditions. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and convenient, Recombinant Protein Expression in Mammalian Cells: Methods and Protocols aims to aid researchers in building on our knowledge of protein structure and function and to speed the discovery of new therapeutic proteins.