Manual is common use in our life. Nearly all of these products have a manual in our life. There are many different kinds manual. Manual for most non-trivial software applications are book-like documents with contents similar to the above list, the Strata User Manual is a good example of this type of document. Some documents have a more fluid structure with many internal links. The Google Earth manual is an example of this format. The term manual is often applied to document that addresses a specific aspect of software product, some usages are installation guide, getting started guide, and various how to guides. A good manual can help people easy to operation, easy to understand. Manual is useful in our life.