This page takes the place of two webpages that no longer exist:

• http://www.akpeters.com/QANDO
• http://ww2.lafayette.edu/~smithder/qando.htm.

Page 10 of On Quaternions and Octonions refers to the first of those webpages as the place to go for additional information and for a link to the online version of John Baez’s paper, “The Octonions.”  The second of these promises has now just been fulfilled; for the first please consult the current errata.

(October 28, 2013)