How are you?' You go, 'Hi,'" she said. Parents and caregivers can now find Ms. Rachel's new books, "100 First Words," "My First Coloring Book" and "Potty Time with Bean," wherever books are sold.

YouTube sensation Ms. Rachel is jumping off the screen and onto the page by releasing four original books for little ones. Fans of Ms. Rachel and her channel, “Songs For Littles,” now have ...