Once the appropriate technical protocols have been delineated, the best quality images obtained, and the cases queued up on PACS, the diagnostics responsiblity reaches the radiology reading room. The radiologist must do more than simply "lay words on" but reach a real conclusion. If we cannot reach a definitive diagnosis, we must offer a reasonable differential diagnosis. A list that's too long is usless; a list that's too short may be misleading. To be useful, a differential must be more than a rote recitation from some dusty book or a mnemonic from a lecture way back when. Instead, we must take into account key imaging findings and relevant clinical information. With these considerations in mind, we a Amirsys designed our Expert Differential Diagnosis series-- EXPERTddx for short. Leading experts in every subspecialty of radiology identified the top differential diagnoses in their respective fields, enfompassing specific anatomic locations, generic imaging findings, modality-specific findings, and clinically based indications. Our expects gathered multiple images, both typical and variant, for ecah EXPERTddx. Each features at least eight beautiful images that illustrate thepossible diagnoses, accompanied by captions that highlight the pertinent imaging findings.