ALL IN ONE 英語全分野を制覇 is an iPhone app that offers a comprehensive solution for learning English. Developed by Yosuke Oki, this full version app falls under the Education & Reference category. The app is designed to help users master the English language in all its aspects, including vocabulary, grammar, reading, listening, and more. Unlike other apps that require separate downloads for each aspect of the language, ALL IN ONE offers all the learning materials in one place. The app is based on the popular English learning book with the same name, which has sold over 310,000 copies in Japan alone and has been translated and published in Taiwan, China, and Korea. This app includes 419 example sentences with natural speed audio, 3600 intermediate to advanced level vocabulary and phrases, and 400 intermediate to advanced level grammar points.