余幼业儒，读张子西铭∶天下疲癃生理残障，皆吾兄弟。韩子原道∶为之医药，以济其夭死。深叹二公之言，民胞物之
心也。然膺HT 任，惟宰相上佐天子，调燮阴阳，节宣元气，庶足起疲癃而寿国脉。余诵之，直欲于身亲见之，殊庸劣鲁
钝，为时所厄，会家君医学揭来燕豫，附应中原，医之正传，已有所得。余因省焉，遂弃儒就学，绍岐黄仓越之心传，
阐刘张朱李之秘诀，于当时云游高士有裨医教者，尤竭诚晋谒，与之上下其议论。远宗先哲，近取名公，殚精竭神，磨
光刮垢，与家君相为渊源，盖有年矣。每视疾则公诊以脉息，次察其病原。而攻治之法，方药之制，又酌其脉病而投之。
执是以往，影响不殊。既而以脉病治方，分门别类，以古今之确论为枢要，间亦窃附已意，参互考订，遗者补之，略者
详之，纂辑成帙。医有十三科，此其初备，厘为八卷，名以《古今医鉴》。夫医，意也。何取于鉴？鉴惟空而后无遗照，
医必明而后无遗疾。是书上考诸古，古之明验者取之；下质诸今，今之明验者取之。虽隐伏沉痼，罔不洞察，与鉴之照
物，妍媸不爽，有相类者，此之谓医鉴。此余命名意也。 甫成，不敢自秘，爱付诸梓，以公诸天下后世，俾医有小补，
病有救援。视医国良相，故小大不同，而疲癃可起，夭死可苏，亦菀乎张、韩二公之用心。余不佞言之无文，聊述成书
之概于篇端，其订讹正误，尚有俟于后之君子。
时万历己丑仲冬之吉金溪后学龚廷贤书于恒我斋。
我年轻时研习儒家经典，读到张载的《西铭》：“天下所有的疲病、残疾和生理残障之人，都是我的兄弟。”又读到韩愈的《原道》：“应当提供医药，来救济那些夭折早逝的人。”我对这两位先贤的话深感赞叹，认为他们体现了将百姓视为同胞、视万物为同类的情怀。然而，承担治理重任的，唯有宰相辅佐天子，调和阴阳，疏导元气，才足以使疲病者康复，使国家命脉长寿。我诵读这些话语，直切地想要亲身践行，但我资质平庸愚钝，被时势所困。恰逢家父医学著作问世，流传于燕赵豫地，呼应中原地区，中医的正统传承，已有所收获。我因此反思省悟，于是放弃儒学转而学习医学，继承岐伯、黄帝、仓公、扁鹊的心法传承，阐发刘完素、张从正、朱震亨、李东垣的秘诀。对于当时云游四方、对医学教育有贡献的高士，我尤其竭诚拜访，与他们上下探讨议论。远尊奉古代先哲，近取法当代名家，耗尽精力心神，打磨去粗取精，与家父相互渊源，已有多年了。每次诊治疾病，我先通过脉息进行诊断，其次观察疾病的根源。而攻邪治疗的方法，方剂的配制，又斟酌脉象与病情后投药。坚持这样做，疗效如影随形，毫不差池。后来我将脉诊、病因、治疗方法及方剂，分门别类整理，以古今确切的论述作为核心要点，偶尔也附上自己的见解，互相考证订正，遗漏的加以补充，简略的加以详述，编纂成册。医学分为十三科，此书初步完备，分为八卷，命名为《古今医鉴》。医学，在于心意（领悟）。为什么要用“鉴”（镜子）作比喻？镜子因为空灵所以能毫无遗漏地映照万物，医生必须明理所以能毫无遗漏地发现疾病。这本书上考察古代，选取古代明确验证过的内容；下质询当今，选取当今明确验证过的内容。即使是隐伏难见的沉疴痼疾，没有不能洞察清楚的，这与镜子照物，美丑不差毫厘，有相似之处，这就叫作“医鉴”。这就是我命名的用意。刚完成书稿，不敢私自珍藏，于是交付刻印，向天下后世公开，希望给医者带来小小的帮助，让病人得到救援。虽然这与治理国家的良相相比，大小不同，但能使疲病者起身，使夭死者复苏，也符合张载、韩愈两位先贤的用意。我不才，言语缺乏文采，只是在篇首简要陈述成书的概况，其中纠正错误、修正谬误的工作，还有待于后来的君子来完成。
万历己丑年仲冬吉日，金溪后学龚廷贤在恒我斋书写。
In my youth, I studied Confucianism and read Zhang Zai's *Xi Ming* (Western Inscription): "All the weary, disabled, and physically impaired in the world are my brothers." I also read Han Yu's *Yuan Dao* (On the Way): "One should provide medicine to rescue those who die prematurely." I deeply admired these words of the two sages, recognizing in them a spirit of regarding all people as kin and all things as part of one's own body. However, those who bear the responsibility of governance are only the Prime Minister who assists the Son of Heaven in harmonizing Yin and Yang (the opposing forces of nature) and regulating Yuan Qi (Original Vital Energy), so that the weary may recover and the nation's vitality may endure. Reciting these words, I earnestly desired to practice them personally, but being mediocre and dull, I was constrained by the times. Fortunately, my father's medical works were published and circulated in the regions of Yan, Yu, and Zhongyuan, aligning with the orthodox transmission of Chinese Medicine. I reflected upon this and thus abandoned Confucian studies to learn medicine, inheriting the esoteric transmissions of Qi Bo, Huang Di, Cang Gong, and Bian Que, and elucidating the secrets of Liu Wansu, Zhang Congzheng, Zhu Zhenheng, and Li Dongyuan. For eminent scholars who traveled widely and contributed to medical education at that time, I sincerely visited them to discuss theories up and down. Revering ancient philosophers from afar and taking contemporary masters as examples, I exhausted my mind and spirit, polishing and refining knowledge, maintaining a profound connection with my father for many years. Whenever treating diseases, I first diagnosed through pulse diagnosis (Pulse Diagnosis), then observed the etiology of the disease. The methods of attack and treatment, and the preparation of prescriptions, were determined by weighing the pulse and the condition before administering herbs. Adhering to this approach, the therapeutic effects were immediate and accurate. Later, I categorized pulse diagnosis, etiology, treatments, and formulas into sections, using established theories from ancient and modern times as the core principles, occasionally adding my own insights, cross-referencing and verifying, supplementing omissions, and detailing brevities, compiling them into volumes. With the thirteen branches of medicine preliminarily covered, I organized them into eight volumes, naming it *Gu Jin Yi Jian* (Mirror of Medicine Through the Ages). Medicine lies in understanding (Intent). Why use "Jian" (Mirror) as a metaphor? A mirror is empty and thus reflects everything without omission; a doctor must be clear-minded and thus detect all diseases without omission. This book examines the past, selecting verified cases from antiquity; it questions the present, selecting verified cases from contemporary times. Even hidden and chronic diseases are thoroughly discerned, similar to how a mirror reflects objects without distorting beauty or ugliness. This is what I mean by "Medical Mirror." This is the intention behind the title. Upon completion, I dared not keep it secret, so I had it printed and made public to the world and future generations, hoping it would offer slight assistance to physicians and aid patients. Although this differs in scale from governing a state like a capable minister, it can revive the sick and restore the prematurely dead, fulfilling the intent of Zhang Zai and Han Yu. Lacking eloquence, I merely outline the genesis of this work at the beginning; correcting errors and rectifying mistakes remains for later scholars.
Written by Gong Tingxian, a junior scholar from Jinxi, at Hengwo Studio, on an auspicious day in the second month of winter during the Jichou year of the Wanli era.