Originally published in 1977, these examples of research and scholarly argument were collected in honor of Professor Sidney W. Bijou. In the language of academics, they constitute a Festschrift: a festival of scholarly writing, performed to celebrate the career of a person who produced, and stimulated others to produce, exactly such contributions throughout a long, valuable, and productive professional history. Since 1955, Dr Bijou had worked almost exclusively within the approach variously labelled as the functional analysis of behavior, the experimental analysis of behavior, operant conditioning, or Skinnerian psychology. From his point of view, it seems clear, the first of these labels was the correct one. It was the principle of objective, direct, observable analysis that attracted him.