"The Calculus 7" by Louis Leithold is a renowned textbook that has been a staple in the field of calculus for decades. First published in 1967, the book has undergone several revisions, with the seventh edition being the most recent. The book is widely regarded as a comprehensive and rigorous treatment of calculus, making it an ideal resource for students and instructors alike. In this write-up, we will review the key features and benefits of "The Calculus 7" by Louis Leithold, with a focus on the PDF version.