When one poet reads another poet, it is like one explorer studying the maps of a predecessor. If the complete works of a poet are a world map of his own making, then to be influenced by another poet is to have the map of his writing placed over your own. Every time another strong influence is experienced, another map is placed on top of a growing pile of maps, which adds up to a weight of influence. And then, if the poet is lucky enough, he discovers his own way of writing, and at that point all the accumulated maps of his reading become transparencies, through which we look into the palimpsest of the new poet’s psyche.
—Billy Collins, in PEN America 15