1. Introduction. 1.1. Overview. 1.2. Formulas for the Weil representation. 1.3. The case, where H is unitary and the place v splits in E -- 2. On certain residual representations. 2.1. The groups. 2.2. The Eisenstein series to be considered. 2.3. L-groups and representations related to P[symbol]. 2.4. The residue representation. 2.5. The case of a maximal parabolic subgroup (r = 1). 2.6. A preliminary lemma on Eisenstein series on GL[symbol]. 2.7. Constant terms of E(h, f[symbol]). 2.8. Description of W(M[symbol], D[symbol]). 2.9. Continuation of the proff of Theorem 2.1 -- 3. Coefficients of Gelfand-Graev type, of Fourier-Jacobi type, and descent. 3.1. Gelfand-Graev coefficients. 3.2. Fourier-Jacobi coefficients. 3.3. Nilpotent orbits. 3.4. Global integrals representing L-functions I. 3.5. Global integrals representing L-functions II. 3.6. Definition of the descent. 3.7. Definition of Jacquet modules corresponding to Gelfand-Graev characters. 3.8. Definition of Jacquet modules corresponding to Fourier-Jacobi characters -- 4. Some double coset decompositions. 4.1. The space Q[symbol]. 4.2. A set of representatives for Q[symbol]. 4.3. Stabilizers. 4.4. The set Q\h[symbol] -- 5. Jacquet modules of parabolic inductions : Gelfand-Graev characters. 5.1. The case where K is a field. 5.2. The case K = k[symbol]k -- 6. Jacquet modules of parabolic inductions : Fourier-Jacobi characters. 6.1. The case where K is a field. 6.2. The case K = k[symbol]k -- 7. The tower property. 7.1. A general lemma on "exchanging roots". 7.2. A formula for constant terms of Gelfand-Graev coefficients. 7.3. Global Gelfand-Graev models for cuspidal representations. 7.4. The general case : H is neither split nor quasi-split. 7.5. Global Gelfand-Graev models for the residual representations E[symbol]. 7.6. A formula for constant terms of Fourier-Jacobi coefficients. 7.7. Global Fourier-Jacobi models for cuspidal representations. 7.8. Global Fourier-Jacobi models for the residual representations E[symbol]