Dr. Navjot S. Sodhi co-advised my M.Sc. thesis research at the National University of Singapore (NUS). As Professor of Conservation Ecology at NUS, he inspired, mentored and trained a generation of young conservation scientists from Southeast Asia and globally. This book, published in 2010, was conceived and edited by Navjot and his close friend and collaborator, Dr. Paul Ehrlich, with the aim of making conservation science education accessible to students and researchers in the tropics, where financial resources are usually limited. Therefore, this book was made freely available to the public (https://conbio.org/publications/free-textbook/) to access and download. It is also notable that this edited volume features a chapter on invasive species written by Dr. Daniel Simberloff, Gore Hunger Professor of Environmental Science at the University of Tennessee, Knoxville. Navjot, unfortunately, passed on in 2011 due to lymphoma. I will always be grateful for his mentorship and friendship, and I will always remember the days I spent with him and his family in Boston when I first visited the US to interview for Ph.D. programs. We all miss you, Navjot.