is a free tool that allows you to view PDF or portable document format files. It was created and distributed by Adobe Systems. It's a cross-platform tool, which means the PDF file will look the same on Windows and Mac, and it also lets you search through PDF files.
Adobe Acrobat, on the other hand, is a more advanced and commercial version of the Reader that includes extra functionality such as the ability to produce, print, and manipulate PDF files. Adobe Acrobat is capable of accomplishing all the Reader can do, and then some.