Books like What's the Big Secret?
Laurie Krasny Brown, Laurene Krasny Brown
What's the Big Secret? is 31 pages, about 34 minutes at 250 words a minute.
9 books to read next
How long each takes
It's So Amazing! 1.6 h 
Mommy Laid an Egg 35 min 
Sex Is a Funny Word 2.9 h 
Tell Me Why 8.8 h 
Where Did I Come From? 53 min 
It's Not the Stork! 1.1 h 
Amazing You! 35 min 
Who Has What? 37 min 
It's Perfectly Normal 1.8 h Bar height shows length. Estimated at 250 words a minute.