Anna Comstock defined the idea extensively in her book, "Handbook of Nature Study": "Nature Study is for the comprehension of the Individual life of the bird, insect or plant that is nearest at hand." Comstock continued that nature study aided "both discernment and in expression of things as they are". The movement came at a time when society was concerned with the future of the next generation and with nature conservation itself, and because of this was met with high regard and high expectations. Though many efforts had come before 1890 by some naturalists and scientists to teach and expand the movement, the nature-study movement really did not gain momentum with the public until the late 19th century. By 1925, the subject had found a place in the curriculum of almost every school district in the United States.