Why did Visual Basic .NET introduce AndAlso and OrElse?
Posted by: Duncan Mackenzie, MSDN
This post applies to Visual Basic .NET 2002/2003/2005
... Prior to VB.NET, the VB language only had the And and Or operators. They were essentially bitwise operators, which means that they took their two operands and performed an AND or OR operation on each bit position to produce the resulting bit...