The tectonic settings and internal characteristics of fold-and-thrust belts are remarkably varied and diverse. They include

• classic thin-skinned Canadian Rocky Mountain-style foreland fold-and-thrust belts (Bally et al., 1966; Price, 1981; Barclay and Smith, 1992);

• basement-involved Laramide uplifts of the western U.S.A. (Schmidt et al., 1993);

• subduction-related thrust systems of the Andes (Ramos et al., 2004 [this volume]), the Zagros (Beydoun et al., 1992), and Papua New Guinea (Cole et al., 2000; Hill et al., 2000; and Hill et al., 2004 [this volume]);

• collision terranes of the Himalayas (e.g., Mugnier et al., 2004 [this volume]), and the Italian Apennines (Coward et al., 1999; Turrini and Rennison, 2004 [this volume]); and

• deep-water, gravitationally driven fold-and-thrust belts, such as those offshore West Africa or in the Gulf of Mexico (Rowan et al., 2004 [this volume]).

Many of these fold-and-thrust belts contain major hydrocarbon accumulations in complex structural traps. Hydrocarbon exploration in many onshore fold-and-thrust belts commonly is very difficult because of rugged and severe terrain, complex structures, and poor-quality seismic data.

Key to understanding the 4-D evolution of fold-and-thrust-belt systems are an appreciation of the driving mechanisms for thrust-belt development, and knowledge of the timing of thrust movements, their burial and thermal evolution, and their uplift and exhumation histories. Understanding both the spatial and temporal evolution of fold-and-thrust belts is vital for viable hydrocarbon exploration and development in these complex terranes. This volume presents key papers that address current issues in understanding fold-and-thrust-belt structures. These include (1) fold-and-thrust-belt geodynamics, (2) 3-D thrust geometries, (3) scaled analog modeling of thrust belts as a means of developing new kinematic models for their evolution, (4) new models of thrust-fault-related folds and synkin-ematic growth strata, and (5) case studies of particular thrust terranes.

Several key topics are addressed in this volume.