My take on a question in Quora:

"Why is skimming and scanning important when reading?"

Generally, for a fast and versatile reader, scanning and/or skimming create the following benefits:

1) they give you a visual-spatial snapshot and gestalt feel of the book prior to reading;

2) they help you to decide whether it’s worthwhile for you to read the book;

3) they create myriad way-finding signposts e.g. text organisational patterns, transition or signal words, headings and subheadings, bold and italics print, boxed selections, footnotes, pictures or photos or diagrams, end-book summary or end-chapter summaries, content tapestry, in the book terrain, to help guide your reading journey, so that you can make expeditious moves into the jugular;