The new articles and reprints in this volume document the life and scientific contributions of British physicist and applied mathematician, Sir Gilbert T Walker (1868-1958). The collection bears witness to Walker's keen insights into statistically based climate prediction, the nature of atmospheric variability on time scales of a year or longer, and the detection and attribution of climate change. Chapter authors include Joy Monteiro, Timothy DelSole, Richard Katz, Jagadish Shukla, and Ka Kit Tung. Part 1 presents an overview of Walker's life and work while he was serving as Director of the India Meteorological Department from 1904 to 1924. Although he instituted many useful reforms, he did not achieve his goal of producing skillful predictions of Indian summer monsoon rainfall. While in India, Walker began writing a series of descriptive papers, based on statistical methods, in which he systematically documented the structure, seasonality, and evolution of the principal patterns of year-to-year climate variability - later known as teleconnection patterns - on a global basis. Part 2 provides an overview of Walker's work on teleconnection patterns. It features a reprint of his most widely cited paper, published in 1932, on his so-called North Atlantic Oscillation, North Pacific Oscillation, and Southern Oscillation. Parts 3 and 4 contain reprints of more recent papers relating to these patterns.