Clyde Tombaugh and the Search for Planet X

From the Series On My Own Biography

  • Interest Level: Grade 2 - Grade 4
  • Reading Level: Grade 3

Twelve-year-old Clyde Tombaugh stepped up and took his first look through a telescope. Gazing at the moon, he was thrilled by the sight of its craters and valleys. What other mysteries were out there in space? Clyde wondered. Learn the fascinating true story of the hardworking young man who discovered Pluto through richly colored illustrations that capture Clyde’s determination and bring his story to life.

Format Your Price Add
Interest Level Grade 2 - Grade 4
Reading Level Grade 3
Category 5 Kinds of Nonfiction, 5KN: Narrative Nonfiction
Publisher Lerner Publishing Group
Brand On My Own Books
Imprint Millbrook Press ™
Language English
Publication Date 2012-01-01
Text Type Narrative Nonfiction
BISACS JNF007000, JNF007090, JNF051040
Dewey 520'.92
Graphics 1-color illustrations, Full-color illustrations
Lexile 700
Guided Reading Level N
ATOS Reading Level 4.5
Accelerated Reader® Quiz 47160
Accelerated Reader® Points 0.5
Features Awards, Reviewed, Teaching Guides, and Timeline


  • Science Books & Films Best Books, Winner, 1996



“. . .This will be an attractive addition to astronomy collections.”

School Library Journal

“This interesting story is simply and directly told. Excellent-quality watercolor paintings appear throughout.”
School Library Journal

Science and Children

“This story is fascinating. . .”
Science and Children

Illustrator: Laurie A. Caple

Lerner eSource™ offers free digital teaching and learning resources, including Common Core State Standards (CCSS) teaching guides. These guides, created by classroom teachers, offer short lessons and writing exercises that give students specific instruction and practice using Common Core skills and strategies. Lerner eSource also provides additional resources including online activities, downloadable/printable graphic organizers, and additional educational materials that would also support Common Core instruction. Download, share, pin, print, and save as many of these free resources as you like!

On My Own Biography

Engage readers’ interest and imagination! These award-winning biographies feature full-page illustrations. Written in story format, each book features pivotal episodes that reveal what kind of person the subject is (or was) and how he or she came to be famous. View available downloads →