Dr. Duncan Wyllie is President of Wyllie & Norrish Rock Engineers based in Vancouver, Canada. He has been working exclusively in the field of applied rock engineering for almost fifty years, initially in underground and open pit mining and then in civil engineering. He has worked on slope, tunnel, landslide, blasting and foundation projects throughout North America, as well as in such countries as India, Ethiopia, Sri Lanka, New Zealand, Turkey and Peru. The major portion of this work is for highways, railways and power projects, and involves both new construction and the evaluation and remediation of existing slopes and tunnels. Duncan is also the author of Rock Fall Engineering (2014) and Foundations on Rock (1999), both published by CRC Press. He has prepared manuals on rock slope engineering for the Federal Highway Administration, and taught about 80 courses throughout the U.S. for the National Highway Institute in Washington D.C.