The elements: Si, N, O, C and H, have strong chemical affinities for one another. Under the correct conditions, Si-N bonding will occur in almost any Si-N-(O/C/H), and many related, reaction systems; although Si-O and Si-C are formidable competitors to Si-N. The most favored Si-N compound is stoichiometric Si3N4. It comes in three common varieties. How they interrelate, how one finds them and (above all ) how one makes them - and how sometimes they just happen to form - are the subjects of this book, with due attention being paid to closely related matters.