The Boy Scout Explorer series was written under the pen name of Don Palmer--one of only two male pen names Millie used, the other being Frank Bell for her Flash Evans series. This series consisted of only 3 titles:

• volume #1 Boy Scout Explorers at Emerald Valley 1955
• volume #2 Boy Scout Explorers at Treasure Mountain 1955
• volume #3 Boy Scout Explorers at Headless Hollow 1957

The Boy Scout Explorers are a senior branch of the Boy Scouts. This series follows the adventures of The Boys of Explorer Post No. 21 and their Scout Leader, George (Happy) Livingston.