Engelbert Esztherhazy, scion, of aristocracy in Scythia-Pannonia-Transbalkania (fourth largest empire in Europe [the Turks were fifth]), could not have cared less. He had served his country and his Emperor in war; he now led the leisured life of his class. But then events overtook him, caught him up, whirled him about; and when he found his feet again, he was a changed man.

The servant of a visiting king was undoubtedly a shaman. What powers did he command? What other powers were secretly at work behind the familiar scenes of south-eastern Europe?

But also steam, already powering factories, ships and trains -- what more could it do, portent to the changing world of the late nineteenth century? Road transport... or even powered flight? Think of the dread possibilities for warfare!

But when the Autogóndola-Invention took to the skies over the territories that ambitious neighbors -- viz., Ruritania and Graustark -- wished to claim, was it really its steam engine that made it fly? Or did it depend on the unreckoned aid of sorcery? Between the old knowledge and the new, Eszterhazy was to spend his life, searching. Time and time again, the unexpected would visit him, often leaving the learned Doctor to end a notebook entry with "UNEXPLAINED."

Here are tales of the most gripping such visitations, now brought together in one comprehensive volume. Several of these stories were collected as The Enquiries of Doctor Eszterhazy, a 1975 Warner Books paperbacks, now long unobtainable. These represent less than half of the present volume, which includes stories of his earlier career, published in Amazing Science Fiction Stories under the aegis of George Scithers. A foreword by Gene Wolfe and an afterword by the author complete The Adventures of Doctor Eszterhazy.

"Or All The Seas with Oysters", one of Avram's stylish and witty stories, won the 1958 Hugo award and headed a collection of the same name; among other short story collections are What Strange Stars and Skies, Strange Seas and Shores, and The Redward Edward Papers. His novels range from the far future of Rogue Dragon and Mutiny in Space to the might-have-been Dark and Middle Ages -- comic in Peregrine: Primus and Peregrine: Secundus, haunting in The Phoenix and the Mirror and Vergil in Averno. From 1962 to 1964 he served as editor of The Magazine of Fantasy and Science Fiction. New York City, Mexico, Belize and California have been his haunts; he has been a U.S. Marine in World War II and a sheepherder* in Israel.

*Or shepherd, if you want it to sound romantic.