Celery, Apium graveolens, is the mild, enlarged version of a bitter, thin-stalked Eurasian herb called smallage. Chinese celery (var. secalinum) is closer in form and flavor to smallage, while Asian water celery is a more distant relative (Oenanthe javanica) with a distinctive flavor. Our familiar celery was apparently bred in 15th-century Italy, and remained a delicacy well into the 19th. It consists of greatly enlarged, pleasantly crunchy leaf stalks, or petioles, and has a distinctive but subtle aroma due to unusual compounds called phthalides that it shares with walnuts (hence their successful pairing in Waldorf salads), and terpenes that provide light pine and citrus notes. Celery is often combined with carrots and onions in gently fried aromatic base preparations for other dishes (French mirepoix, Italian soffrito, Spanish sofregit; in the Louisiana Cajun “trinity” of aromatics the carrots are replaced by green capsicums). In parts of Europe, celery has been preferred in a more delicately flavored blanched form, originally produced by covering the growing stalks with soil, then by growing pale green “self-blanching” varieties. Celery is often served raw, and its crispness is maximized by presoaking in cold water. Both celery and celery root contain defensive chemicals that can cause skin and other reactions in sensitive people.