Walter De Maria's Lightning Field (1977) is one of the 20th century's most significant works of art. Situated in a remote area of desert in southwestern New Mexico, it comprises 400 polished, stainless-steel poles (spaced 220 feet apart) installed in a grid measuring one mile by one kilometer. A sculpture to be explored on foot, The Lightning Field is intended to be experienced over an extended period of time.     Critic Kenneth Baker visited The Lightning Field numerous times over the course of the past 30 years in order to write this text. Inspired and challenged by this remarkable artwork, Baker speculates on the course of our contemporary human condition. But, rather than building on ideas in narrative sequence, he deploys quotation to effect multiple perspectives and points of view. Baker's citations and elegantly crafted prose are arrayed--in a metaphorical parallel to De Maria's choreographing of the vast landscape of the American Southwest--to create a compelling text.