For the first-time prison teacher, the contrasts and differences between the outside world and prison are felt immediately. There are bars and gates, guards, guns, distractions, annoyances, and petty rules. Cooperation is often lacking, and threatening situations can be encountered. Inmates are often described as a 'coherent social group' who live together, dress alike, look similar, and know each other well. Their motivation for taking classes differs. Some come to be entertained, some are merely curious, and others have taken a great deal of college work and need the credits. Once class begins, however, even the most striking differences between prison and campus classrooms can be overlooked. Purposes remain the same: imparting knowledge, stimulating creative thought, and encouraging students. The lack of a supportive social structure, rather than the students themselves, remains the major obstacle to learning. The most successful teachers seem to understand how to adjust their styles of teaching to prisons and manage to hold enrollments stable. It is imperative to obtain a full picture of the inmates' lives and routines from personal observation, discussion with inmates, and talks with guards and other staff members. Making classes as interesting as possible, implementing creative teaching strategies, incorporating a liberal interpretation of prison rules, getting a precise idea of the academic preparedness of students, and evaluating progress through short-term assignments and class participation are important aspects of the successful instructor's work.