This randomized parallel group study will assess the efficacy and safety of erlotinib [Tarceva], as monotherapy or intermittent dosing with docetaxel, in second-line setting in former-smoker male patients with advanced or metastatic squamous non-small cell lung cancer. Patients will be randomized to receive either Tarceva (150 mg/day orally) as monotherapy or 4 cycles of docetaxel (75 mg/m2 intravenously every 3 weeks) plus Tarceva (150 mg/day orally, days 2-16 each cycle) followed by Tarceva monotherapy. Anticipated time on study treatment is until disease progression.