Series are small groups of images edited together to create a cohesive whole. A series might be the culmination of a focused project, or it might be a group of discrete images shot over time that work together, echoing and strengthening one another.
Prints of images in each series are available for purchase in limited edition. Information here.
New series are released periodically, usually every few months.
The most recent is Overlays 2016 Vol. 1, added on February 13, 2016.