|About automorphic representations of reductive groups, we want to understand the basic structures, which includes the Langlands functorial transfer to or the Langlands functorial transfer from other groups. This is the problem which has been studied for years. In this lecture, we start with brief review of the Langlands functorial transfer from the odd orthogonal group to the general linear group for generic cuspidal automorphic representations (the work of Cogdell, Kim, Piatetski-Shapiro, Shahidi, the work of Ginburg, Rallis, Soudry, and the work of Jiang, Soudry). Then we report my recent work (including my joint work with David Soudry) on (1) how to characterize the endoscopic structure of generic cuspidal automorphic representations in terms of the fundamental L-fnctions (D.J. to appear in IMRN 2006) (2) how to establish the Langlands functorial transfer for non-generic cuspidal automorphic representations (D.J.-D.S. work in progress for cuspidal representations with special Bessel models).