Looking for a great piano course to help you improve your skills? Look no further than the John W. Schaum Piano Course! This workbook, titled "The Purple Book," is a great option for early intermediate to intermediate level pianists looking to hone their skills in music theory and piano playing. Published in 1945 by Belwin Inc in the United States, this book is a part of the popular "Piano Course" series. With a focus on American English and the piano as the main instrument, this book is perfect for anyone looking to improve their abilities in playing the piano. Whether you're a seasoned pro or just starting out, the John W. Schaum Piano Course is a great choice for anyone looking to take their piano playing to the next level.