David Pogue 
OS X Yosemite: The Missing Manual [PDF ebook] 

With Yosemite, Apple has unleashed the most innovative version of OS X yetand once again, David Pogue brings his expertise and humor to the #1 bestselling Mac book. Mac OS X 10.10 includes more innovations from the i Pad and adds a variety of new features throughout the operating system. This updated edition covers it all with something new on practically every page.Get the scoop on Yosemites big-ticket changes Learn enhancements to existing applications, such as Safari and Mail Take advantage of shortcuts and undocumented tricks Use power user tips for networking, file sharing, and building your own services