Thirty years is a long time on an undertaking and to wait for the product. It is nearly thirty years since
an article in The Library Journal outlined the system. Thirty years of growth and change have run out
in this glass of time since the classification was applied in the Library of the College of the City of New
York. The conditions there during a period of twenty years permitted of experiment and development in
this work. That it has been adaptive to changes has been very advantageous. The changes there,
however, have diverged from the original embodiment, and the changes that have been made in the
author's published volume are otherwise divergent.