As noted earlier in the week, our featured article focus in August’s Cold Spring Harbor Protocols is on gene transfer into stem cells. The first featured protocol presented a method for using lentiviral vectors as the means for getting your gene of interest expressed. Alhough viral vectors are highly efficient, their use can raise concerns about recombination, immune responses and other safety issues. In contrast, DNA transposons offer an effective, alternative method for nonviral gene transfer that avoids the safety concerns associated with viral vectors. Use of the Sleeping Beauty Transposon System for Stable Gene Expression in Mouse Embryonic Stem Cells from Catherine Krull and colleagues at the University of Michigan provides a method for stable integration and reliable long-term expression of a transgene. Sleeping Beauty transposon-based transfection is a two-component system consisting of a transposase and a transposon containing inverted repeat/direct repeat sequences that result in precise integration into a TA dinucleotide. Like all of our featured articles, this protocol is freely accessible to subscribers and non-subscribers alike.