Thames & Hudson have a great book exploring Bridget Riley's work in context of the era it was produced. Her geometric works reflect the 60's desire to unite body and mind through hallucinogenic drugs, fears of what advances in science held for the future including nuclear war and the need for audience participation in art.
Good friends Sarah Parker, Rachel Lattimore and Joanna Dudderidge have kept the Riley atheistic alive in their shoot for Feral Magazine. See more here http://sarahparkercreative.blogspot.com/
Embodied Visions is available at Artwords, Broadway Market.