The genius of Carl Friedrich Gauss (1777-1855) and the velty of his work (published in Latin, German, and occasionally French) in areas as diverse as number theory, probability and astromy were already widely ackwledged during his lifetime. But it took ather three generations of mathematicians to reveal the true extent of his output as they studied Gauss' extensive unpublished papers and his volumius correspondence. This posthumous twelve-volume collection of Gauss' complete works, published between 1863 and 1933, marks the culmination of their efforts and provides a fascinating account of one of the great scientific minds of the nineteenth century. Volume 2, which appeared in 1863, supplements Volume 1 with additional articles on number theory. It also contains book reviews and posthumous papers, including an unfinished eighth chapter of the Disquisitiones arithmeticae.