Source: http://en.wikipedia.org.License: All Rights Reserved.

The Google logo used from May 31, 1999 until May 5, 2010, changing from ITC New Baskerville to Catull and dropping its exclamation point.

Source: http://en.wikipedia.org.License: All Rights Reserved.

The Google logo in 1998, used until May 30, 1999.

Source: http://en.wikipedia.org.License: All Rights Reserved.

The Google logo from May 6, 2010 to September 19, 2013. The major difference in comparison to the previous logo (valid since May 31, 1999) is the reduced distance of the projected shadow behind the word Google and the change in color of the yellow "o" to orange.

Source: http://en.wikipedia.org.License: All Rights Reserved.

On September 19, 2013, Google released a new logo, dropping all the bevels and shadows of the previous incarnations. Also, some of the lettershapes were adjusted, simplifing the crossbar stroke in the 'e' and the terminals of several other letters.