Penguin Readers is a graded reading series for English Language Teaching (ELT) markets, designed for teenagers and young adults learning English as a foreign or second language.

It is May 1940. Western countries are falling into Nazi hands. Britain must prepare to be invaded any day. The future of the world lies on the shoulders of one man. This is the story of how British Prime Minister Winston Churchill changed history over twenty-five difficult days during World War II.

Penguin Readers is a series of popular classics, exciting contemporary fiction and thought-provoking non-fiction, written for learners of English as a foreign language. The series is aligned to the Common European Framework of Reference for Languages and includes language activities that help develop key skills.

Darkest Hour, a Level 6 Reader, is B1+ in the CEFR framework. The longer text is made up of sentences with up to four clauses, introducing future continuous, reported questions, third conditional, was going to and ellipsis. A small number of illustrations support the text.