This book serves several purposes. The first and foremost is to give an elementary introduction to the basic concepts of the theory of ordinary representations to finite groups with a minimum of prerequisites. The second purpose, which is also the main theme of this exposition, is to be able to do the theory rather explicitly for the important special case of the symmetric groups Sn of permutations on n letters. The third purpose is to use the preparatory material of the first two parts, coupled with the Sn theory, to do the same for some other important special groups, namely, the alternating group An and the hyperoctahedral groups Bn and Dn.