Adobe Reader is a software designed to securely view PDF documents. PDF stands for Portable Document Format and its biggest advantage is the fact that it has cross-platform compatibility. You can open a PDF file on a Linux computer, or Windows, or even on your mobile phone if it has Symbian. This format was created in 1993 by Adobe Systems, but because it was hard to make it popular in the beginning, Adobe decided to start releasing Adobe Reader for free, in order to beat the competition of other formats such as Common Ground Digital Paper, Envoy. Nowadays, PDF is the standard for printable documents and it's widely used for publishing e-books. PDF has undergone a lot of changes and updates, eight in total, corresponding to the number of Adobe Reader versions, with 8.0 being the latest one.

A PDF file contains vector graphics (for shapes and lines), text and raster graphics (for photos). The latest PDF versions support hyperlinks inside the document, forms, JavaScript and there all types of plug-ins that can extend its functionality even further.

There are several advantages that have contributed to the popularity of PDF. It supports full-text search in the whole file. It produces files with smaller size, so you can upload your files on the Web without worrying about download times. The ability to optimize PDF files is another advantage. The navigation trough the documents is made really easy thanks to the clear interface, more on which you can read in this article.

A great benefit associated with Adobe PDF is the fact that such files look and print exactly as intended across a wide variety of platforms. The Adobe Reader software is free and easy to download from the official website or at http://www.freesecuredownloads.com/acrobat/index.html. Over the past years, it has gained tremendous popularity with more than 200 million downloads. Hence, it's the most effective way of distributing documents to a broad audience across a broad range of operating systems.

An inside look of a PDF file reveals that the structure consists of - header, body, cross-reference table, and trailer. The header holds the version of PDF. The body is the document itself with all objects that carry information, like fonts, images, words, etc. The cross-reference table is filled with pointers to all the objects in the PDF file. The trailer contains pointers to the xref table and to key objects contained in the trailer dictionary.

In order to create PDF files, you need Adobe Reader, but if you don't want to spend money on this software, you can download PDF creation program, and there are plenty of them available online. Adobe Acrobat though, is the most comprehensive tool allowing a single user to create and interact with PDFs. You can create files by scanning paper documents, which the software will renter as text, so you will be able to search trough it, or even edit it. Digital source of information are also an option. The paper-to-digital conversion is made possible with Adobe Capture, available in Personal or cluster Edition.

1. Navigating in Adobe Reader

To make the most out of this software, you need to get familiar with all its capabilities and interface. There is so much more than what you see at first glance.

Adobe Reader is available as a standalone application or it could be opened inside a browser window, but either way, the interface is almost the same. It consists of a document pane at the center that displays PDFs, and a navigation pane on the left holding buttons that allow you to navigate through the document.

- Creating PDF files:

As mentioned, there are different methods of actually creating PDF files, one of which is available through the Reader. Just go in the File menu – Create Adobe PDF Online. Your IE browser will open http://createpdf.adobe.com. You must register for an account in order to use this service. Once logged in, click on ‘Convert to Adobe PDF' and browse to select the file on your local computer. Select the desired options and press Create PDF.

- Dealing with Toolbars:

First check if the Toolbars are unlocked by right-clicking on the main toolbar on top and see if the option Lock Toolbars is unchecked. You can move toolbars from side to side, you can choose which ones you like to hide or show and if you select the More Tools option, you will be given a list of all the available toolbars.

- Changing the View:

To change the navigation pane view, click one of the buttons to the left of the navigation pane. If you want to customize the display colors for page background and document text, choose Edit > Preferences > Accessibility. To set the default zoom level and page layout, choose Edit > Preferences > Page Display.

You can switch between Reading Mode and Full Screen Mode, available in the View menu. In Full Screen Mode, all toolbars are hidden, Adobe Reader fills the whole screen, so that you can focus easily on the content. In Reading Mode, the navigation pane and toolbars are hidden, just the menu bar is present.

- Updating Adobe Reader:

Adobe Reader can be updated in various ways. The update process can be automatically triggered by a specific PDF file, for example, one that contains unknown language fonts, then the Reader will as you whether you want to download the fonts. You can choose to make the updates manually by selecting the last option in the Help menu - Check for updates. This feature will connect to the central Adobe server and see if any new components are available. If that's the case, you will be given a list of the updates that are about to be installed, but once again, manual confirmation is required.

If you want to set automatic updates, go to Help > Check For Updates, in the Adobe Updater window, click Preferences and select Automatically Check For Adobe Updates. The last thing to do is specify whether you want weekly or monthly updates.

2. Working with PDF files in Adobe Reader

Adobe Reader provides users with plenty of different ways to manipulate PDF files. Of course, it allows you to view them, save them in PDF or in text format, or search the entire content of a file.

We all know that a search is performed by clicking on Find in the Edit menu, or Ctrl+F. This is all good, but if you want to search all PDFs in a given folder, press Edit > Search and select ‘All PDF Documents in'.

Should you want to convert a PDF file into a text document, go File > Save as Text, and the file will be saved with ‘.txt' extension. No content will be lost except for the images.

To use portions of the PDF content in other files, you can Copy and Paste the selected text. In case the Cut, Copy and Paste commands are not available, this means that the author of the document has set restrictions against copying the text.

Copy and Paste functions are not applicable just plain text, but for images as well. Using the Select Tool, draw a rectangle surrounding the given image, right click and select Copy.

3. Movies, Sounds and 3D models in PDF

PDF is a very rich format and it can include various multimedia features, like video clips, digital audio, and even 3D models that can readers can move, zoom in/out and examine piece by piece.

The main multimedia formats that can be embedded are Flash, MPEG, MP3, QuickTime and Windows Media files. The activation of such content requires the reader's approval in order to prevent playing multimedia from unverified sources. To change this default behavior of Adobe Reader, go into the Preference menu > Multimedia Trust and check the permissions.

To add 3D models inside your PDF file, you need Adobe 3D, which supports a variety of three dimensional file formats. You can even embed 3D CAD models. User interaction with such file types is simple. Just click on the 3D model with the Hand or Select Tool to activate it. The 3D toolbar will open up and the animation will be played.

4. Working with PDF forms

Adobe PDF forms are basically a computerized version of a paper form, which the user must fill out and send over via email, CD or publish it on a website. PDF forms are especially useful for ebooks, so that readers can test their knowledge by answering a test (in a PDF form), which is then send to a server so that results can be estimated.

- Types of Forms:

PDF forms can be quite simple, just consisting of blank fields or they can be interactive. The interactive ones are designed to be submitted on the Internet. The Form type is determined by the method of distribution. The following types are available:

- Fill-in & Print forms – the user enters text in static fields, saves the PDF file and then prints it out

- Submit-by-email - such forms contain a button which sends just the data inputted by the user, attaching the complete PDF from into an email message

- Submit-online PDF forms - all data is send to a server for further processing. This option is only available when the Adobe Reader is open in Web-based mode.

To send the data you have entered in a PDF form, press the Submit button.