In this special thematic series, eight papers contribute new advances on robotic exoskeleton technology and our understanding of how humans respond to mechanical assistance from robotic exoskeletons. Herr starts off with a review on exoskeletons and orthoses, highlighting major accomplishments and discussing future directions in the field [
15]. Herr is more conservative than I have been in my prediction of widespread exoskeleton use, as he states it is hopeful that exoskeletons will be in common use by the end of the 21
st century. In a second review in the thematic series, Crespo and Reinkensmeyer focus on control strategies that have been used for robotic movement training after neurological injury [
16]. The control strategies used for rehabilitation exoskeletons are likely to have a large impact on their success, so this is an area of research that needs substantial effort in the future. Staying in the broader area of rehabilitation exoskeletons, Mankala et al. present a novel exoskeleton design for gait training [
17], and Westlake and Patten communicate results from a pilot study on gait training after stroke [
18]. In the area of exoskeletons for studying human movement physiology, Sawicki describes a robotic knee-ankle-foot orthosis under proportional myoelectric control [
19], and Noel et al. provide some interesting results on adaptation to mechanical forces from a robotic ankle orthosis [
20]. The thematic series ends with two excellent contributions on energy harvesting exoskeletons. The first transmits negative mechanical work at the knee into electrical energy [
21], and the second uses pneumatics to store energy during stance for powering dorsiflexor assistance during swing [
22].