This guest editorial describes ways teachers can use guessing games about an unknown item in a "mystery box" to help children improve their abilities to listen to others, recall information, ask purposeful questions, classify items by class, make inferences, synthesize information, and draw conclusions. The author presents information from a qualitative analysis of 90 preservice teachers' reflections on using mystery boxes with preschool through elementary students in urban public school settings in central New York State. Children were enthusiastic about the game, used a variety of strategies to generate questions, experienced difficulties in paying attention, remembering and synthesizing information, and had difficulty focusing on more than one characteristic at a time. Errors included repetition of questions and class inclusion/exclusion errors. Modeling, thinking out loud, and giving hints helped children become successful. Creating one's own mystery box, exercises in identifying attributes and classifying items, and practice in questioning techniques are among suggested follow-on activities.