This book is concerned with frequency in foreign language learning, and in particular with contrastive frequency across languages. The focus is on the learning of English and Italian, whether it be English speakers learning Italian or Italian speakers learning English. Despite the fact that frequency - whether it be of lemmas or of word forms within specific lexicogrammatical environments - lies at the heart of L2 learning, it is not stressed in any salient or consistent manner in English / Italian language-learning materials. This work aims to redress the balance, offering a corpusassisted critical analysis of the way frequency is handled in English and Italian dictionaries, and bringing out unexpected differences between the two languages.