Too often, the sales process is all about fear.

Customers are afraid that they will be talked into making a mistake; salespeople dread being unable to close the deal and make their quotas. No one is happy.

Mahan Khalsa and Randy Illig offer a better way. Salespeople, they argue, do best when they focus 100 percent on helping clients succeed. When customers are successful, both buyer and seller win. When they aren't, both lose. It's no longer sufficient to get clients to buy;...