In fact, very much wider information could be obtained under Section 29. There is nothing underhand about the way this information is obtained. It is quite well known that returns have to be made in order to determine the composite rate. When the information is obtained, it has to be linked with the particular taxpayer's individual file for purposes of calculating the rate. If it is found that the taxpayer has not disclosed some of his income, it is the duty of the Revenue to investigate it.