Apple's website, Apple.com, offers official manuals for Apple computers, as of 2015. The Support section of the website provides user guides for a variety of Apple computer models.
From the Apple website home page, click Support in the navigation bar. Scroll down to the bottom of the page, and click Manuals in the footer under Resources.
The Manuals page lists the most popular user manuals. Click the link for your product, or click Browse by Product. Type the computer model name in the search field, or click a product icon that best describes your computer. Scroll through the displayed results, and choose the manual that fits your needs.