Margaret Penrose was a house pseudonym used by the Stratemeyer Syndicate. This name was used for books like Dorothy Dale (1908), Dorothy Dale at Glenwood School (1908), Dorothy Dale's Great Secret (1909), Dorothy Dale and Her Chums (1909), Dorothy Dale's Queer Holidays (1910), The Motor Girls (1910), The Motor Girls on a Tour (1910), Dorothy Dale's Camping Days (1911), The Motor Girls at Lookout Beach (1911), The Motor Girls Through New England (1911), The Motor Girls on Cedar Lake (1912), Dorothy Dale's School Rivals (1912), Dorothy Dale in the City (1913), The Motor Girls on the Coast (1913), Dorothy Dale's Promise (1914), The Motor Girls on Crystal Bay (1914), Dorothy Dale in the West (1915), The Motor Girls on Waters Blue (1915), Dorothy Dale's Strange Discovery (1916), The Motor Girls at Camp Surprise (1916), and Dorothy Dale's Engagement (1917).