learning SQL

Hi,

I am using the following statement to copy records from a table called Main into another called Main1:

Insert into Main1
Select * from Main where tType = 'test';

However, I am getting the following Error:

Msg 8101, Level 16, State 1, Line 1
An explicit value for the identity column in table 'Main1' can only be specified when a column list is used and IDENTITY_INSERT is ON.

Thanks