We now have back the Percy Goetschius Serious Composer Series. Books are available in both print and PDF.
Dr. Goetschius\' books, in the suggested order of study, are:
1) Elementary 18th Century Counterpoint
2) The Homophonic Forms of Musical Composition
3) Counterpoint Applied
4) The Larger Forms of Musical Compositiong
Complete tables of contents of all books are online.