Book reviews : The Battle of Beirut: why Israel invaded Lebanon. By MARTIN JANSEN (London, Zed Press, 1982). 142 pages. £4.50. 'Lebanon Eyewitness', By MARTIN PERETZ in The New Republic (2 August 1982). 'J'Accuse' By NORMAN PODHORETZ in Commentary (September 1982). 'Lebanon: the case for the war' By ROBERT W. TUCKER in Commentary (October 1982)