أهم مصادر الكتاب
| STACE | (1) A Gritical History of Greek Philosophy. |
| وكان عليه أكبر اعتمادنا، ومنه أكثر اقتباسنا | |
| ZELLER | (2) Outline of Greek Philosophy. |
| ERDMANN | (3) History of Philosophy. |
| DURANT | (4) A Story of Philosophy. |
| BURNET | (5) Greek Philosophy. |
| BENN | (6) History of Ancient Philosophy. |
| A. E, BAKER | (7) How to understand Philosophy. |
| LUDWIG NOIRÉ | (8) Development of Philosophic thought from Thales to Kant. |
| DRESSER | (9) History of Ancient and Medieval Philosophy. |
