新实用汉语课本 1-6 (For all levels)
New Practical Chinese Reader 1-6, English-Chinese Version, 2nd Ed.
Ling：New Practical Chinese Reader is good series for Chinese language learners. I have been using its first textbook ( Level 1 ) to teach beginners for a long time, and I really enjoy it!
NPCR 1-2: Beginner – upper beginner
NPCR 3-4: Intermediate – upper intermediate
NPCR 5-6: advanced – upper advanced
Highly recommended for beginners and intermediate level learners.