She received thousands of letters in response to the first book. She wrote two more books on the same topic, "Between the Gates" and "Beyond the Gates". She then wrote a novella about animal rights titled "Loveliness". Phelps said she wrote "The Gates Ajar" to comfort a generation of women who were devastated by the losses of their loved ones following the Civil War and who found no comfort in traditional religion. Phelps' vision of heaven made the book a run-away best seller. She later built on the success of the first Gates book with a series of other books that featured the word "Gates" in their titles and which continued to reinforce her views of the afterlife as a place with gardens, comfortable front porches, and finely built houses.