If you are a student, buy the hardcover or rent the digital edition via Amazon Kindle or Cambridge’s official platform. The second edition is often available used for $50–$80—a small price for the knowledge that defines rotorcraft engineering careers.
Most textbooks skip history, but Leishman understands that you cannot fix a resonance problem without knowing why the Sikorsky VS-300 nearly shook itself apart. He traces the evolution from bamboo tops (ancient Chinese toys) to Juan de la Cierva’s autogyro and Igor Sikorsky’s modern helicopter. This section provides the "why" behind every mathematical model in the later chapters. If you are a student, buy the hardcover