  This is the announcement and partly the review of our results about
classification of Lorentzian Kac-Moody algebras of the rank three. One of our
results gives the classification of Lorentzian Kac-Moody algebras with
denominator identity functions which are holomorphic reflective automorphic
forms with respect to paramodular groups. Almost all of them were found in our
paper ``Automorphic forms and Lorentzian Kac-Moody algebras. Parts I, II'',
Intern. J. Math. 9 (1998), 153-275. Our main result gives classification of all
reflective meromorphic automorphic products with respect to paramodular groups.
  This is mainly a presentation of our lectures given during the Workshop:
``Applications to Quantum Field Theory'', October 23 - 27, 2000, in the Newton
Mathematical Institute at Cambridge.
