Reading Metrics
Grade Level
Middle Grades (MG 4-8)
Book Level
6.0
Points
0.5
Fiction/Nonfiction
Nonfiction
Word Count
1771
Points per Word
0.000282
Page Count
32
Points per Page
0.015625
Description
People have wanted to hide messages and important information for millennia. Read how history’s coolest codes and ciphers have progressed from belts and sticks to rotating disks and supercomputers.