The book contains transcribed data of recorded speeches and lectures by eminent politicians, military officers, business people, and cultural figures in the Taisho and early Showa period. They are based on “Okada Collection of SP recordings” released in May 2010, which is a digitalized version of SP recordings collected by Norio Okada, transcribed by linguists as part of the NINJAL Project “Exploring Variation in Contemporary Japanese: Multiple Approaches (project leader: Masao Aizawa)”. This book will induce not only research on Japanese as public speech in the early 20th century from a historical perspective but also research on politics, economy, and culture of the modern period from a new perspective.