Editing is an art, no doubt, but it is also a craft. And craft is something one learns with help from someone. A typical book on editing might explain some principles and show examples of elements such as editing for content, editing for grammar, editing for flow, editing for style, etc. Editors typically guide authors to insight about things such as content, language, flow, style. The very notion of a collaboration between an author and an editor, whose goal is to perfect the manuscript in every way possible, was borne out of the technological changes coming from the late nineteenth century. The enormous influence that editors can have on both the work of single authors and fashionable styles is expressed by Louis Menand, who writes in The New Yorker: Writers are products of educational systems, but stories are products of magazine editorial practices and novels are products of publishing houses.