The flurry of M&A deals announced in 2011, including AT&T's agreement to acquire T-Mobile USA, ConAgra's proposed bid for Ralcorp, and eBay's acquisition of GSI Commerce, indicate that M&A has returned, and is perhaps headed back to the levels seen before the financial crisis.

Most firms of a certain size will turn to it in their search for growth, forcing almost all managers to face up to the challenge of integration at some point their career. For many managers it is often their first, and only time and M&A is high on the list of things that many managers hate. According to many studies,...