Preface The advance of scientific thought in ways resembles biological and geologic transformation:long periods of gradual change punctuated by episodes of radical upheaval.Twentieth century physics witnessed at least three major shifts- relativity,quantum mechanics and chaos theory-as well many lesser ones.Now, early in the 21st,another shift appears imminent,this one involving the second law of thermodynamics. Over the last 20 years the absolute status of the second law has come under increased scrutiny,more than during any other period its 180-year history.Since the early 1980's,roughly 50 papers representing over 20 challenges have appeared in the refereed scientific literature.In July 2002,the first conference on its status was convened at the University of San Diego,attended by 120 researchers from 25 countries (QLSL2002)[1].In 2003,the second edition of Leff's and Rex's classic anthology on Maxwell demons appeared [2],further raising interest in this emerging field.In 2004,the mainstream scientific journal Entropy published a special edition devoted to second law challenges [3].And,in July 2004,an echo of QLSL2002 was held in Prague,Czech Republic [4. Modern second law challenges began in the early 1980's with the theoretical proposals of Gordon and Denur.Starting in the mid-1990's,several proposals for experimentally testable challenges were advanced by Sheehan,et al.By the late 1990's and early 2000's,a rapid succession of theoretical quantum mechanical challenges were being advanced by Capek,et al.,Allahverdyan,Nieuwenhuizen, et al.,classical challenges by Liboff,Crosignani and Di Porto,as well as more experimentally-based proposals by Nikulov,Keefe,Trupp,Graff,and others. The breadth and depth of recent challenges are remarkable.They span three orders of magnitude in temperature,twelve orders of magnitude in size;they are manifest in condensed matter,plasma,gravitational,chemical,and biological physics;they cross classical and quantum mechanical boundaries.Several have strong corroborative experimental support and laboratory tests attempting bona fide violation are on the horizon.Considered en masse,the second law's absolute status can no longer be taken for granted,nor can challenges to it be casually dismissed. This monograph is the first to examine modern challenges to the second law. For more than a century this field has lain fallow and beyond the pale of legitimate scientific inquiry due both to a dearth of scientific results and to a surfeit of peer pressure against such inquiry.It is remarkable that 20h century physics, which embraced several radical paradigm shifts,was unwilling to wrestle with this remnant of 19th century physics,whose foundations were admittedly suspect and largely unmodified by the discoveries of the succeeding century.This failure is due in part to the many strong imprimaturs placed on it by prominent scientists like Planck,Eddington,and Einstein.There grew around the second law a nearly inpenetrable mystique which only now is being pierced. The second law has no general theoretical proof and,like all physical laws,its status is tied ultimately to experiment.Although many theoretical challenges to it have been advanced and several corroborative experiments have been conducted,Preface The advance of scientific thought in ways resembles biological and geologic transformation: long periods of gradual change punctuated by episodes of radical upheaval. Twentieth century physics witnessed at least three major shifts — relativity, quantum mechanics and chaos theory — as well many lesser ones. Now, early in the 21st, another shift appears imminent, this one involving the second law of thermodynamics. Over the last 20 years the absolute status of the second law has come under increased scrutiny, more than during any other period its 180-year history. Since the early 1980’s, roughly 50 papers representing over 20 challenges have appeared in the refereed scientific literature. In July 2002, the first conference on its status was convened at the University of San Diego, attended by 120 researchers from 25 countries (QLSL2002) [1]. In 2003, the second edition of Leff’s and Rex’s classic anthology on Maxwell demons appeared [2], further raising interest in this emerging field. In 2004, the mainstream scientific journal Entropy published a special edition devoted to second law challenges [3]. And, in July 2004, an echo of QLSL2002 was held in Prague, Czech Republic [4]. Modern second law challenges began in the early 1980’s with the theoretical proposals of Gordon and Denur. Starting in the mid-1990’s, several proposals for experimentally testable challenges were advanced by Sheehan, et al. By the late 1990’s and early 2000’s, a rapid succession of theoretical quantum mechanical challenges were being advanced by C´ˇapek, et al., Allahverdyan, Nieuwenhuizen, et al., classical challenges by Liboff, Crosignani and Di Porto, as well as more experimentally-based proposals by Nikulov, Keefe, Trupp, Gr¨aff, and others. The breadth and depth of recent challenges are remarkable. They span three orders of magnitude in temperature, twelve orders of magnitude in size; they are manifest in condensed matter, plasma, gravitational, chemical, and biological physics; they cross classical and quantum mechanical boundaries. Several have strong corroborative experimental support and laboratory tests attempting bona fide violation are on the horizon. Considered en masse, the second law’s absolute status can no longer be taken for granted, nor can challenges to it be casually dismissed. This monograph is the first to examine modern challenges to the second law. For more than a century this field has lain fallow and beyond the pale of legitimate scientific inquiry due both to a dearth of scientific results and to a surfeit of peer pressure against such inquiry. It is remarkable that 20th century physics, which embraced several radical paradigm shifts, was unwilling to wrestle with this remnant of 19th century physics, whose foundations were admittedly suspect and largely unmodified by the discoveries of the succeeding century. This failure is due in part to the many strong imprimaturs placed on it by prominent scientists like Planck, Eddington, and Einstein. There grew around the second law a nearly inpenetrable mystique which only now is being pierced. The second law has no general theoretical proof and, like all physical laws, its status is tied ultimately to experiment. Although many theoretical challenges to it have been advanced and several corroborative experiments have been conducted