Although Turbo Prolog is no longer actively supported or updated, its influence can still be seen in modern programming languages, such as Prolog, C++, and Java.
The book "Introduction to Turbo Prolog" by Carl Townsend is available in print and digital formats. However, I couldn't find a freely available PDF version of the book. You may be able to find a downloadable version or purchase a copy from online retailers or second-hand bookstores. INTRODUCTION TO TURBO PROLOG BY CARL TOWNSEND PDF