The cover illustrates a multifunctional gene delivery system interacting with cancer cells. Small interfering RNA (siRNA) is an emerging class of therapeutics, which works by regulating the expression of a specifi c gene involved in disease progression. Effective transport of siRNA with minimal side effects remains a challenge. In this study, a nonviral nanoparticle gene carrier was developed which contains a core of clustered superparamagnetic iron oxide nanoparticles and a shell of alkylated polyethyleneimine. This composite effectively binds siRNA with good protection, as demonstrated by an enzymatic degradation assay. Signifi cant down-regulation of luciferase by loaded nanocarriers was observed both in vitro and in vivo. In addition, transfected cells showed signifi cant MR imaging contrast compared to nontransfected ones. For more information, please read the Full paper “N-Alkyl-PEI-Functionalized Iron Oxide Nanoclusters for Effi cient siRNA Delivery” by H. Ai, X. Chen, and co-workers beginning on page 2742.