The authors consider the fourth order quasilinear difference equation D 2 p n jD 2 x n j a21 D 2 x n þ q n jx n j b21 x n ¼ 0;where a and b are positive constants and {p n } and {q n } are positive real sequences. They classify the nonoscillatory solutions according to their asymptotic behavior for large n and then give necessary and sufficient conditions for existence of solutions of these various types. The results are illustrated with examples.