The mother of all Buddhas is the
Avatamsaka Sutra. Translated as the
Flower Adornment Sutra, it is huge in size and overflowing with wisdom, compassion & power.
Master Hua gave a nine-year commentary on it. Here are a few of his comments on this sutra:
http://cttbusa.org/dharmatalks/fas.htm
Here is brief summary on all 39 chapters of the
Avatamsaka Sutra:
http://www.buddhistbooks.info/avatam/content.html