A characteristic of being a professional is the internalisation of the collective professional theory (CPT)--the shared insights of professionals. Problems arise when different opinions stemming from professionals' personal professional theories (PPTs) obscure a CPT's content. This study argues that cooperating professionals' CPTs form a so-called field and can be represented by concept maps. The relations between PPTs, CPTs, and fields are examined for the fields of accountancy and teaching. The results indicate that CPTs are more complex than PPTs, and that the teachers' field is more diverse than the accountants' field. These insights are important because socialisation in a field may be fostered if one is aware of CPTs and the surrounding field in relation to one's PPT.