On Certainty is "Wittgenstein's most fascinating and challenging work," says British scholar Danièle Moyal-Sharrock. It is a dramatic, brilliant and investigative text, where the great thinker can be appreciated in the midst of analysis and philosophical questioning. Moyal-Sharrock sheds light in these pages on the intellectual adventure of following the Viennese philosopher along the tracing of his thought, adjusting to his nuances of development, to the subtleties of his inner allusions, to the precise weight of his emphases, to the sometimes deceptive use of his words, and to the obscure and yet inevitable interweaving of the various threads of his intellectual work. For Moyal-Sharrock, one of Ludwig Wittgenstein's greatest achievements is to point out the categorical error, which philosophy scholars make time and time again, between what we can know and what we are certain of without knowing.