gr. 4-6:
The Gilgamesh epic poem is from Sumer. There is a trilogy version that would be appropriate for your older ones (say 8 yr. old and up) from Ludmila Zeman-http://www.amazon.com/Gilgamesh-King-Trilogy-Ludmila-Zeman/dp/0887764371/ref=wl_mb_hu_m_9_dp
YOu Wouldn’t want to Be a Sumerian Slave-Jacqueline Morley (lighthearted)
First Book of Ancient Mesopotamia and Persia-Charles Robinson
Ancient Mesopotamia-Virginia Schomp
Science in Ancient Mesopotamia-Carol Moss
For your own reading so you can in turn educate:
Sumerians/Ur of the Chaldees-C. Leonard Woolley (archaeologist who first excavated Sumer)
HTH,
Rachel