In 1999, the Swallowtail publishing house published three books about the adventures of the boy detective Leroy Brown, nicknamed “Encyclopedia,” from the small provincial American town of Idaville (translation by Oleg Georgievich Bitov; the books are freely available on the Internet). The author of these books is the American writer Donald J. Sobol. During his life, among many other works, he wrote about 30 books about the adventures of Encyclopedia Brown. What "Swallowtail" has released are collections of stories taken from various books. The fourth book in this series is offered to you as it first appeared in print. Some of the stories were included in various “Makhaon” collections. Others are being translated into Russian for the first time (although there is only one in this book).