We report an experiment investigating the effects of conditioning books as reinforcers for observing responses on the learning of textual responses by pre-school children. The independent variable was the acquisition of conditioned reinforcement of observing responses and choice of book stimuli in free play settings where children could choose to play with toys or look at books. Prior to the conditioning procedures, the children played with toys and did not look at books in free time in 4 preconditioning 5-minute free-play sessions. During the treatment we conducted simultaneous stimulus conditioning procedures until looking at books became the preferred free-play activity. The dependent variable consisted of the numbers of learn-units-to mastery of textual responses before and after conditioning books as reinforcers for observing responses. Three boys and one girl (ages 2 years and 9 months to 4 years) participated in the experiment in a pre and post learn-units-to-criterion and simultaneous matched-pairs design with a time-lagged component. Prior to reinforcement conditioning, we matched children in pairs based on learn units they required to master a sets of 5 counterbalanced word sets. One child in each of 2 pairs received book conditioning initially, and another child received an equal number of conditioning trials with toys, as a control conditions, and then book conditioning. The results showed that (1) all four children required fewer learn-units-to-criterion on textual responses after books were conditioned as reinforcers for choice and observing and those who received the book conditioning first performed best. (2) Three of the four children maintained preference for books at 33%, 83%, and 100% of time in free play probes at 1 month. (3) There were no maintenance effects on accuracy of textual responding. (Contains 2 tables and 6 figures.)