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Alternator Books; Cryptology (Alternator Books) Books in Order

2 books by Rachael L. Thomas. Reading level: Grades 5.7–6. Middle Grades (Ages 9–12).

Series books grow with readers — but that's also the trap. Most series start at one reading level and one content intensity and drift upward over the course of the run. Alternator Books; Cryptology (Alternator Books) (2 books by Rachael L. Thomas) lands at reading level Grades 5.7–6, with average content intensity 1.5/5. Intensity stays consistent across the series — a kid who can handle the first book can generally handle the rest.

The reading-order table below lists every book with per-volume reading level and intensity badges so you can spot any escalation before it catches your reader off guard. For a deeper dive into how we score text difficulty vs. emotional weight separately — and why series readers especially benefit from that split — see our methodology page.

2
Books
Grades 5.7–6
Reading Level
1.5/5
Avg. Intensity
MG
Middle Grades

Content Intensity Across the Series

Consistent

Content stays at a steady intensity level throughout the series.

1
2
First book Latest book

Alternator Books; Cryptology (Alternator Books) Reading Order

# Title Reading Level Content
1 Classic Codes and Ciphers
Rachael L. Thomas
Level 6 Gentle
2 Secrets of Navajo Code Talkers
Rachael L. Thomas
Level 5-6 Mild

Questions about the Alternator Books; Cryptology (Alternator Books) series

What reading level is the Alternator Books; Cryptology (Alternator Books) series?
The Alternator Books; Cryptology (Alternator Books) series by Rachael L. Thomas is at a Grades 5.7–6 reading level (average Grade 5.8). Intended for Middle Grades (Ages 9–12). There are 2 books in the series.
What order should I read the Alternator Books; Cryptology (Alternator Books) books?
The reading-order table above lists all 2 books with per-volume reading level and intensity ratings. Start with book 1 and read in publication order unless the table indicates a different recommended order for newer readers.
What age is the Alternator Books; Cryptology (Alternator Books) series appropriate for?
The Alternator Books; Cryptology (Alternator Books) series is recommended for Middle Grades (Ages 9–12). The average content intensity is 1.5/5. Check the intensity trajectory above to see whether content gets heavier across the series — if it does, sensitive readers may want to stop earlier in the run.