A general theory of superconductivity is developed, starting with a BCS Hamiltonian in which the interaction strengths (V11, V22, V12) among and between "electron" (1) and "hole" (2) Cooper pairs arc differentiated, and identifying "electrons" ("holes") with positive (negative) masses as those Bloch electrons moving on the empty (filled) side of the Fermi surface. The supercondensate is shown to be composed of equal numbers of "electron" and "hole" ground (zero-momentum) Cooper pairs with charges +/-2e and different masses. This picture of a neutral supercondensate naturally explains the London rigidity and the meta-stability of the supercurrent ring. It is proposed that for a compound conductor the supercondensate is formed between "electron" and "hole" Fermi energy sheets with the aid of optical phonons having momenta greater than the minimum distance (momentum) between the two sheets. The proposed model can account for the relatively short coherence lengths xi observed for the compound superconductors including intermetallic compound, organic, and cuprous superconductors. In particular, the model can explain why these compounds are type 11 superconductors in contrast with type I elemental superconductors whose condensate is mediated by acoustic phonons. A cuprous superconductor has 2D conduction bands due to its layered perovskite lattice structure. Excited (nonzero momentum) Cooper pairs (bound by the exchange of optical phonons) above T(c) are shown to move like free bosons with the energy-momentum relation epsilon = 1.2v(F)q. They undergo a Bose-Einstein condensation at T(c)= 0.977hv(F)k(B)-1n1/2BAR, where n is the number density of the Cooper pairs. The relatively high value of T(c) (approximately 100 K) arises from the fact that the density n is high: n1/2 approximately xi-1 approximately 10(7) cm-1. The phase transition is of the third order, and the heat capacity has a reversed lambda (lambda)-like peak at T(c).
