What makes PDF (Portable Document Format) unique is that it can provide an exact electronic replica of any document from any application on all major platforms, including all text, graphics and fonts. It's an amazingly flexible format with a myriad of uses ranging from electronic manuals and e-books, through secure document exchange and archiving, to multimedia presentation and high-end commercial print.

Acrobat is the name Adobe has given to its technology built around the PDF, and in many ways Acrobat's flexibility is its problem as much as its strength. In particular, it can be difficult for users to get their head around just what Acrobat can do for them. That's why, with this latest release, Adobe has chosen to split the technology into a family of four increasingly powerful applications: Adobe Reader, Acrobat Elements, Acrobat Standard and Acrobat Professional. Unfortunately, Adobe had only released the Professional version at the time of going to press, so it's impossible to be precise about every individual feature that each version will offer, but the target audiences and dividing lines are clear.

The first rung on the ladder is the PDF viewer application previously known as Acrobat Reader and now renamed Adobe Reader. This is the version of Acrobat you'll almost certainly use even if you aren't interested in creating your own PDFs, as it's both free to use and distribute – authors can bundle it with their PDFs. So what's new apart from the ability to open files created with Adobe Acrobat 6's new PDF 1.5 format?

There's nothing too drastic to report in terms of the interface, but there are changes such as the new How To window on the right, providing access to task-based HTML help (assuming this finds its way into Adobe Reader – all Adobe is currently saying is that it will have a similar styling to Acrobat 6 Professional). This side panel is also used for the new Microsoft-style Search feature, which lets you search through multiple PDFs without needing a pre-created index. The toolbars have also changed to include friendlier icons, most of which have text labels next to them, while more advanced features are accessed via drop-down menus.

For the Professional version (and possibly others), new navigation and viewing features include a Split view for viewing different parts of your document simultaneously and a Layers navigation pane for hiding and showing layered content. Zoom levels up to a stunning 6,400 percent are now supported and there's greater viewing control available via a Pan and Zoom window (this lets you set up the current zoom area interactively) and a Loupe tool that magnifies the area under the cursor (great for tiny captions).

Most eye-catching, or ear-catching, is the new Read Out Loud command available on supporting operating systems, although Microsoft Sam's flat voice and intonation soon grate.

Starting to write

Adobe Reader caters for the free consumption of PDFs; the rest of the Acrobat family is where you start paying. Acrobat Elements is the cheapest option, but it's only available to enterprise for volume licensing. The dividing line is that Acrobat Elements enables users to create their own PDFs. Traditionally, this has been taken care of by Acrobat Distiller, which converts PostScript print-to-disk files to PDF. This could be brought into play from any application via the Adobe PDF printer driver.

However, Adobe has recognised that Distiller and the whole idea of 'printing' to PDF was off-putting and little understood, so has done everything it can to push it into the background. The emphasis instead is on the one-click automatic creation of PDFs from all the major Office applications. Macro-based 'Convert to PDF' icons are automatically added to Word, Excel, PowerPoint and now Outlook too. It's even possible to right click on a supported file in Windows Explorer and convert from there.

Moving up the ladder, Acrobat 6 Standard lets you combine files from different applications into a single document. The new Add Headers and Footers command adds consistent page numbering, while Add Watermark and Background lets you set up a shared look and feel. If you combine multiple JPEG images into a single PDF, you can use the new Picture Tasks commands to export, edit and print your photos based on imposition layouts.

As well as converting file formats to PDF, Acrobat Standard offers the ability to capture to PDF. The simplest version of capturing is the ability to convert a clipboard image. Paper Capture, which scans and converts existing documents, is in a different league. The scan is automatically OCRed so that the resulting text is searchable and the PDF size is kept to a minimum – ideal for archiving (especially if security is important, thanks to Acrobat's 128-bit encryption).

Even better is Acrobat's Web Capture. This lets you automatically convert Web pages and entire Websites to a single, easily archived PDF. Now the capability is built into Internet Explorer, which also supports in-browser viewing (this is also promised for Netscape 7). So you browse as normal, and then switch to PDF to automatically store pages you want to keep. With its integrated Explorer Bar side panel, you can quickly target different PDFs to organise your permanent Web archives by subject.

But creating the PDF is only part of the story. With Acrobat 6 Standard, Adobe wants to make PDFs part of your everyday workflow, which means targeting workgroup collaboration. Acrobat has always offered commenting tools with which to annotate your PDFs, but their use has been pretty crude - the digital equivalent of plastering your document with sticky notes and then passing it on to the next user. Now the whole process has been overhauled.

The first sign of this is a revamp of the commenting tools. These have been rationalised with the less common options – such as Text Box, File Attachment and new Drawing options – moved to an Advanced Commenting toolbar. Meanwhile, the basic tools have been rethought. With the Text Edit tool it's now possible to automatically mark up insertions, deletions and replacements. The pop-up Note windows offer colour-coding, roll-over connector lines, background spell-checking, basic text formatting and even customisable semi-transparency.

Adding your comments is only part of an efficient workflow: someone needs to initiate and control the whole process. This is simple to do with the new Send by Email for Review command with which you send the PDF and instructions to all interested parties. When users have added their annotations, they just hit the Send Comments command to send their response.

Rather than resending the edited PDF, this actually sends an FDF (Form Data Format) file to the originator; opening it automatically incorporates all comments into the single master file. Even more efficient for networked users or those with a WebDAV-enabled server is the Upload for Browser-based Review. This automatically adds all comments to the single master PDF, which is browsable and editable by all (you can also now reply to existing notes to create comment threads).

And that's not the end of Acrobat Standard's review capabilities. To manage the collaboration process, it offers the Review Tracker side panel so the initiator can check who's responded and remind those who haven't. When all comments have been gathered, it allows you to print out side-by-side pages and comments with connector lines, though it's considerably easier to work your way through them with the reworked Comments navigation pane.

Here you can filter and sort all comments and set their status to accepted or rejected. If the original document was a Word XP file, it's