7 theories are presented for understanding & preventing suicidal behaviour from a criminological perspective. Lester asserts that traditional ways of studying suicide have failed, & that theories derived from the study of criminal behaviour may offer new insights. These perspectives include: 1) a classical theory; 2) a positivist individualistic theory; 3) a social structure theory; 4) a learning theory; 5) a social control theory; 6) a social reaction theory; & 7) a social conflict theory.