While interest in the problem has waxed and waned over the years, it has never completely disappeared, and recently the topic has come back into vogue, with many papers published over the past 10 years and more due in the next year It is interesting to note how people s views have changed over the years Minkowski was originally thought to be correct, although whether this was due to the convincing nature of his proposal, or people s dislike of Abraham is unclear. In 1950 M.V. Laue [3] was quite conclusive that Minkowski had developed the correct tensorial solution, and his views continued to be held through to the early 1970s without questioning. At this time experiments were undertaken which proved the existence of the Abraham force, and the opinion began to swing in favour of Abrahams tensor as being the correct solution. Recently though views have changed again, towards understanding that both are correct but in different circumstances It appears Minkowski derived his energy-momentum tensor independent of any other work; however Abrahams was not formulated separately, but was an attempt to reformulate minkowski's tensor without the extra 'minkowski force term. his goal was to preserve the form from classical mechanics-a derivative with respect to time. In a previous paper Abraham had developed a system for the electrodynamics of objects in motion, which, while consistent with Maxwell and Hertz, also incorporated ideas by Lorentz and minkowski. While dealing with Minkowski's ponderomotive force, Abraham derived another ponderomotive force and stated that his satisfied relativity At first sight it seems strange that such a small problem from the early twentieth century is still of interest. the author believes there are two contributing factors 1. Physicists do not like unsolved problems. It spoils the 'neatness'(well whatever neatness we have left after Heisenberg and quantum theory! )of the subject. There must be one definite mathematical formula for a particular problem. a case like this is particularly annoying, where the two equations are equivalent sometimes, yet at other times only one will solve a problem 2. As optics becomes ever-increasingly important due to its use telecommunications etc, any area with unanswered questions is worth investigating. We cannot tell what future technological breakthroughs it may lead to Many physicists and mathematicians have proposed alternative tensors that they claim do not suffer the same problem and will describe all situations. The author is not mathematically accomplished enough to comment on the accuracy of their claims. However, most have gone un-noticed and unreferenced by other paper from which the author deduces that none have solved the problem completely rather they reformulate it, sometimes clarifying areas, other times providing yet another layer of complexity over the problem This paper will start by providing an overview of the life of Abraham and minkowski followed by background theory. Next the opinions of physicists over the past century will be considered and the arguments they put forward to support their position will be examined. Finally, some of the experiments undertaken will be4 While interest in the problem has waxed and waned over the years, it has never completely disappeared, and recently the topic has come back into vogue, with many papers published over the past 10 years and more due in the next year. It is interesting to note how people’s views have changed over the years. Minkowski was originally thought to be correct, although whether this was due to the convincing nature of his proposal, or people’s dislike of Abraham is unclear. In 1950 M. V. Laue [3] was quite conclusive that Minkowski had developed the correct tensorial solution, and his views continued to be held through to the early 1970s without questioning. At this time experiments were undertaken which proved the existence of the Abraham force, and the opinion began to swing in favour of Abraham’s tensor as being the correct solution. Recently though views have changed again, towards understanding that both are correct but in different circumstances. It appears Minkowski derived his energy-momentum tensor independent of any other work; however Abraham’s was not formulated separately, but was an attempt to reformulate Minkowski’s tensor without the extra ‘Minkowski force’ term. His goal was to preserve the form from classical mechanics - a derivative with respect to time. In a previous paper Abraham had developed a system for the electrodynamics of objects in motion, which, while consistent with Maxwell and Hertz, also incorporated ideas by Lorentz and Minkowski. While dealing with Minkowski’s ponderomotive force, Abraham derived another ponderomotive force and stated that his satisfied relativity. At first sight it seems strange that such a small problem from the early twentieth century is still of interest. The author believes there are two contributing factors: 1. Physicists do not like unsolved problems. It spoils the ‘neatness’ (well, whatever neatness we have left after Heisenberg and quantum theory!) of the subject. There must be one definite mathematical formula for a particular problem. A case like this is particularly annoying, where the two equations are equivalent sometimes, yet at other times only one will solve a problem. 2. As optics becomes ever-increasingly important due to its use in telecommunications etc, any area with unanswered questions is worth investigating. We cannot tell what future technological breakthroughs it may lead to. Many physicists and mathematicians have proposed alternative tensors that they claim do not suffer the same problem and will describe all situations. The author is not mathematically accomplished enough to comment on the accuracy of their claims. However, most have gone un-noticed and unreferenced by other papers, from which the author deduces that none have solved the problem completely; rather they reformulate it, sometimes clarifying areas, other times providing yet another layer of complexity over the problem. This paper will start by providing an overview of the life of Abraham and Minkowski, followed by background theory. Next the opinions of physicists over the past century will be considered and the arguments they put forward to support their position will be examined. Finally, some of the experiments undertaken will be