The image on the cover illustrates the partition of a coplanar waveguide integrated with a microfluidic channel into regions of approximately uniform cross sections. The coplanar waveguide consists of two metal ground lines surrounding a metal signal line that passes through all of the regions. A microchannel is located in Region 2. S-parameter measurements on the coplanar waveguide, both when the channel is empty and when it is filled with water, are used to determine the fractions of power absorbed in the metal in each region and in the water in the microchannel. The article by Geist et al. in this issue, page 177 provides a complete description and use of the waveguide. Cover illustration adapted by C. Carey.