Agatha Christie is the most widely published author of all time and in any language Now Collins has adapted her famous detective novels for English language learners These readers have been carefully adapted using the Collins COBUILD grading scheme to ensure that the language is at the correct level for an intermediate learner This book is Level 3 in the Collins ELT Readers series Level 3 is equivalent to CEF level B1 with a word count of 11,000 20,000 words