Back in November Contributing Editor Jay Mallin told the story of three photographers that turned their passions into obsessions by meticulously documenting their favorite subject matter

That dedication has paid off for one of the profiled photographers, Michael Collier, who has been documenting geology with aerial photos for nearly 30 years. A book of his work, Over the Rivers: An Aerial View of Geology will be out in October (Mikaya Press, $35)