Let G be a connected reductive algebraic group of characteristic zero. Let B be a Borel subgroup of G. If \(\Psi\) is a dominant character of B then there is a corresponding irreducible representation \(V_ G(\Psi)\) of G on the space of global sections \(\Gamma\) (G/B,L(\(\Psi)\)) of the line bundle L(\(\Psi)\) on G/B corresponding to \(\Psi\). In these two papers the author gives a geometric method of decomposing the tensor product \(V_ G(\Psi_ 1)\otimes V_ G(\Psi_ 2)\) for two dominant characters \(\Psi_ 1\), \(\Psi_ 2\) into its irreducible constituents with their multiplicities. He considers the variety G/B\(\times G/B\), with the diagonal action of G. Then there is an invertible, G-linearized sheaf \(M(\Psi_ 1,\Psi_ 2)=\pi\) \(*_ 1L(\Psi_ 1)\times \pi\) \(*_ 2L(\Psi_ 2)\) on G/B\(\times G/B\) where \(\pi_ 1\), \(\pi_ 2\) are the two projections on G/B. The problem of computing the decomposition of \(V_ G(\Psi_ 1)\otimes V_ G(\Psi_ 2)\) is then equivalent to computing the Euler characteristic \[ \chi (M(\Psi_ 1,\Psi_ 2))=\sum_{i}(-1)\quad iH\quad i(G/B\times G/B,M(\Psi_ 1,\Psi_ 2)). \] The author gives a method of doing this by inductively computing \(\chi (M(\Psi_ 1,\Psi_ 2)|_{\tilde S})\) where \(\tilde S\) is a Schubert variety in G/B\(\times G/B\) corresponding to a ``special'' Schubert variety in G/B. This calculation is described explicitly for the general linear group in the first paper and for the classical groups in the second paper. There is also an appendix in the second paper on how to decompose an irreducible representation of G when restriced to a large reductive subgroup.