In this book you will find the exhibition of research conducted in a classroom of Primary Education in a public school in Mallorca. Its main purpose: to understand the relationship established between teaching practice and theoretical knowledge that support the daily work of a master. One of the methods used, and one of its many merits also: clearly show how the teacher and students are jointly building knowledge through dialogue. In this ethnographic study it is not to describe what happens but fundamentally to interpret what happens, discover the meaning and significance of the actions of the teacher and put the theoretical framework that justify a practice or reverse. Bridges and interrelationships between theory and practice are constant and their exposure is clear and systematic.