What is CBDT ?

Central Board of Direct Taxes (CBDT) : 

The Central Board of Direct Taxes is a statutory authority functioning under the Central Board of Revenue Act, 1963. 
The officials of the Board in their ex-officio capacity also function as a Division of the Ministry dealing with matters relating to levy and collection of direct taxes.The Central Board of Revenue as the apex body of the Department, charged with the administration of taxes, came into existence as a result of the Central Board of Revenue Act, 1924. Initially the Board was in charge of both direct and indirect taxes. 
However, when the administration of taxes became too unwieldy for one Board to handle, the Board was split up into two, namely the Central Board of Direct Taxes and Central Board of Excise and Customs with effect from 1.1.1964. 
This bifurcation was brought about by constitution of two Boards u/s 3 of the Central Board of Revenue Act, 1963.

Composition and Functions of CBDT:

The Central Board of Direct Taxes consists of a Chairman and following six Members: -
Chairman
Member (Income-tax)
Member (Legislation & Computerisation)
Member (Personnel & Vigilance)
Member (Investigation)
Member (Revenue)
Member (Audit & Judicial)