David Eugene Smith 
Teaching of Elementary Mathematics [PDF ebook] 

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. If this work shall help, even in a small way, to open a wider field, or to offer a better point of view, to some one just entering the profession, the author will feel repaid for his labors.