1. They sat on the floors or leaned against book stacks and walls. 2. A central reading room offers access to open and closed book stacks . 3. It is flanked by two-story, red-oak book stacks to the east and west. 4. The Regenstein's overflowing collection posed space problems for the book stacks . 5. The original name of this code is " book stack ". 6. The middle ring, which is built of reinforced concrete, holds the heavy book stacks . 7. The middle area, which contains the heavy book stacks , is made of reinforced concrete. 8. Smoke detectors, designed to protect miles of book stacks , are 35 years old and untested. 9. The circulation desk area has two-tiered bronze-trimmed book stacks . 10. Library features include glass floors in the book stacks and ornate copper-faced shelving and stairs.