Article: The table of contents, in the beginning of the book, is one, big outline of the structure of the book. Take some time to internalize the structure of the book, as provided in the table of contents, before you move on to scanning the book. What you're doing is giving your brain a mold to fit little bits of pieces of information into. If you don't internalize the structure of the book and just start scanning, your brain has to piece together the structure of the theme by itself before it can begin organizing information. This takes time and mental effort. Eliminate that effort by studying the table of contents for 30 seconds before you start reading. A lot of the time, introductions will map out where the writing is going to go, while the ends of chapters often summarize what the author talked about over the course of the chapter. The beginnings of paragraphs will often give the reader a glimpse into topic sentences, which announce what the theme of the paragraph(s) is going to be about. After the topic sentence usually comes some form of evidence or justification. If done properly, reading just the topic sentence will let you know the theme of the paragraph without needing to process the evidence that comes with it. The ends of paragraphs will often be transitions to the topic sentences of the following paragraph. If you read the last sentence of the paragraph and then the first sentence of the next one, you're more likely to understand the topic sentence. Different kinds of books require different ways of scanning. A newspaper article is designed to be skimmed, while a math book is patently not. Before jumping into your speed-reading exercise, decide how much of the book you want to scan and whether you can save any time for more in-depth reading. Works of fiction are notoriously difficult to scan. You don't know how the book is going to turn out, and there's not really a "guide" within a table of contents. If you're reading a book of fiction, take a minute or two to read (not scan) a portion of the book that you think is important. Getting a flavor for detail will help your comprehension of the plot immensely. What use is scanning if you don't remember or understand the most important parts of the book? Give yourself leeway to stop when things get interesting. Really try to ingest these important parts of the book. They'll be the waypoints along your journey that you stop at.  Sometimes, text books will announce that an important concept is about to be introduced. A special bolded section or a portion of design will make it clear that you should slow down and interact more with the material here. If you're reading a novel, for example, read a short summary of a chapter before you scan. This way, you'll be able to identify the most important parts. When you come to those parts while scanning, you'll know that you're supposed to slow down. Sometimes, people re-read sentences without ever knowing that they do it; to cut down on re-reading, read slower. If you're reading quickly but need two times to understand the information, you're probably not going to be able to scan as fast as someone who reads slower but only reads once. Cover a line in your book with a dark piece of paper once you finish scanning it. That way, you won't be tempted to re-read the line once you're done going over it. After each line, move the paper down. Practice scanning your book at least once a week for 30 minutes. During this time, see how many pages you can blaze through while still retaining information. The next week, try to beat your previous mark without sacrificing any information retention.

What is a summary?
Look at the table of contents. Read introductions and ends of chapters. Read the beginnings and ends of paragraphs. Scan depending on the book. Stop when things get important. Try not to re-read sections. Practice, practice, practice.