Leaving the world of the stage, Poole began to concentrate on full length fiction. In the spring of 1912 he began research on the waterfront environs of Brooklyn Heights, New York, gathering observations and anecdotes that he would painstakingly work into shape for the first of his major novels, "The Harbor," which was accepted by Macmillan in the spring of 1914. Physically and emotionally drained by the writing process, Poole spent two months in Europe before returning to the family's new home in the White Mountains of New Hampshire to begin work on his next book.