Book excerpt: The new age of biologic treatment of the ACL is coming. In The ACL Handbook: Knee Biology, Mechanics, and Treatment, the authors cover the past and current state of ACL injuries and treatment, and then introduce and explain the key concepts for understanding the new biologic approach to ACL treatment. The use of factors to enhance graft healing are reviewed, as well as an in-depth review of the science of platelet-rich plasma and its cellular components (platelets, white cells, and plasma). Chapters on in vitro models for science as well as the advantages and disadvantages of animal models for ACL research are included, as are chapters on the new technique of bio-enhanced ACL repair. All are discussed in easily readable text aimed at anyone with an interest of what is coming next in ACL surgery.