The first Big Little Book, The Adventures of Dick Tracy, was published in December 1932. It opened the floodgate for these small (3 5/8 " by 4 1/2"), thick (212 to 432 pages, averaging 1 1/2" thick) juvenile books that usually featured comic strip characters, radio characters, or movie (and later, television) stars. For most, the format was simple: even numbered pages contained prose, odd numbered pages contained an accompanying drawing. An added feature to many of the books were the flip pages -- by flipping the pages fast, small drawings in the upper corners would move, cartoon-like. The format was popular. Although Whitman was the major publisher, ten other publishing companies have issued similar books over the years. Whitman published the books through to 1988; a far as I can tell, the last Big Little Book (Star Wars - Attack of the Clones) was issued by Chronicle Book in 2002. (Chronicle Books issued only ten Big Little Books, 1997-2002, all based on popular films.)
A few of the Whitman Big Little Books eliminated prose altogether and reprinted popular comic strips, one panel to a page. Such was the case with 1942's Invisible Scarlett O'Neil, which reprinted story arcs from the previous years. (Scarlett O'Neil would get the regular Big Little Book treatment later with Invisible Scarlet O'Neil vs The King of Slums.)
Invisible Scarlet O'Neil was created, drawn, and written by Russell Stamm, a former assistant to Chester Gould for Dick Tracy, running from 1940 to 1956, although for the last year or so the title was changed to Stainless Steel. Scarlet O'Neil was a young woman who gained the power of making herself invisible by pressing a certain nerve in her left hand. Of course she uses her power to help others and help police catch bad guys. And since the strip appeared in family newspapers whenever Scarlet turned invisible, her clothes did also.