Memoirs of the American Mathematical Society 2009; 106 pp; softcover Volume: 201 ISBN10: 082184427X ISBN13: 9780821844274 List Price: US$66 Individual Members: US$39.60 Institutional Members: US$52.80 Order Code: MEMO/201/945
 The author proposes a general mechanism by which strange nonchaotic attractors (SNA) are created during the collision of invariant curves in quasiperiodically forced systems. This mechanism, and its implementation in different models, is first discussed on an heuristic level and by means of simulations. In the considered examples, a stable and an unstable invariant circle undergo a saddlenode bifurcation, but instead of a neutral invariant curve there exists a strange nonchaotic attractorrepeller pair at the bifurcation point. This process is accompanied by a very characteristic behaviour of the invariant curves prior to their collision, which the author calls `exponential evolution of peaks'. Table of Contents  Introduction
 Statement of the main results and applications
 Saddlenode bifurcations and sinksourceorbits
 The strategy for the construction of the sinksourceorbits
 Tools for the construction
 Construction of the sinksource orbits: Onesided forcing
 Construction of the sinksourceorbits: Symmetric forcing
 Bibliography
