Theoretical and phenomenological problems concerning J(sup P)=1+ mesons

From both the experimental and theoretical points of view, the researches on J (sup P) = 1+ mesons have been very important for hadronic physics. The complex problems involving these states (particularly regarding the determination of resonances and other non-resonant effects) have occupied a great part of the hadron-hadron phenomenology literature in the last decade. A description of the principal views of the subject is given with a particular emphasis on the case of the A1(→pπ) meson because it is the most important source of papers on J(sup P)=1+ objects and presents still now, open problems. An almost exhaustive of references on the subject and correlated topic is given. (Author)