¿Ser o estar? teaches the basic uses and contexts of these tricky verbs, with special emphasis on the differences between the words. The volume also proposes practical use of these verbs in real situations. The grammar books of Colección Paso a paso are appropriate for both the self-directed student who wants to focus on grammar outside of the classroom, and the teacher who is looking for new techniques in grammar instruction. Topics are presented intuitively and in manageable segments, and language skills are arranged by level of difficulty.