For the D.El.Ed PET exam, the best books are:

1. "D.El.Ed Entrance Exam Guide" by Arihant Experts

2. "D.El.Ed. Entrance Exam Guide" by RPH Editorial Board

3. "Kiran's D.El.Ed PET Exam Guide" by Kiran Prakashan

4. "D.El.Ed PET Exam Solved Papers" by Pustak Mahal

5. "General Knowledge and Current Affairs" by Manohar Pandey

Also, refer to NCERT books for basic concepts