Factory Service Manuals can be purchased in either in a book form or on a CD. The book form is generally the most widely spread, and it is very self explanatory; it comes with table of contents and index. The table of content then breaks down into sections such as Engine, Brakes, Suspension, Body, Wiring, Chassis, Interior, Front Axle, Rear Axle, Exhaust and Emission system, electrical components, and etc. Then each section is broken down into components.
Manuals on CD is a newer form, and it may not be available for your car. They are often in a PDF file format, so you would need an Adobe Reader to read it. Adobe Reader is free and you can get it from Adobe's website. It comes with everything that a book format has. The CD also often comes with this amazing feature that each referenced sentence or section is linked, and you can just simply click on the link, and then you will be to that page. Another words if you are reading on how to change your brake rotors, before you change your brake rotors, you have to uninstall your brake pads. An Uninstalling Brake Pads section will be linked in the Brake Rotors section, and you can just click on the link, and you will be in the Brake Pads section without flipping or finding pages like in the book form. This linked feature is also available for your Index section as well.
So which type of service manual form should you purchase? Well, if you don't like storing a thick book in your garage or bookshelf, or afraid the book might get wore down or tear pages, you could probably consider purchasing the service manual in a CD form, especially with the linked feature. If you don't like reading your manual on a computer, you can also just print the sections or pages you want from your computer. If you end up printing all the pages from your computer, you might as well just buy the factory service manual in a book form to save you money on the ink and paper because there are simply just too many pages.