从前有一个贫穷的农夫名叫螃蟹，赶着两头牛拉了一车木头进城，以二个金币的价格将木头卖给了一个大夫。 大夫一边给他点钱，一边坐在桌旁吃饭，农夫看见大夫的饭菜如此丰盛，从内心感到羡慕，心想如果自己也是大夫该多好。 他站在那里楞了一会儿，终于不好意思地问他是否也能当一名大夫。 "噢，可以，"大夫说："那很好办。""我该作什么？"农夫接着问。 "首先买一本卷首有一只公鸡的入门书；然后将你的牛车和两头牛换成钱，给自己买些衣服和随便一些与医药有关的物品；最后做一块招牌上面写着：'我是万事通大夫，'钉在你的门上边。"农夫照此作好了一切，便开始行医治病。 时间不长，有一个大财主的钱财被盗，听说在某某村庄有个万事通大夫，他想他一定知道被盗的钱财在哪里。 于是大财主套上马车，驱车奔向那个村庄，问螃蟹是不是万事通大夫。 没错，我就是，他答道。 财主邀请他同去把被偷盗的钱财找回来。 "噢，可以，可是我的老婆，革里特也必须去。'"财主同意了，请他们二人上车，一同上了路。 当他们到了那位大人物的豪宅时，餐桌已经摆好，螃蟹被邀请入座就餐。 "好吧，可是我的老婆，革里特也得入座呀。"他说，然后和他的老婆一块坐在了桌旁。 这时第一个仆人端着一盘精美的菜肴进来，农夫用胳膊肘推了他老婆一下说："革里特，这是第一个。"他的意思是这是第一道菜。 然而那个仆人却以为是说："这是第一个贼。"实际上他就是贼，所以他十分害怕，跟外边的同伙说："大夫全都知道，我们可要倒霉啦，他说我是第一个。"第二个不敢进来了，可是他不得不进来。 当他端着菜进来时，农夫用胳膊肘推了他老婆一下说："革里特，这是第二个。"这个仆人同样吓得不轻，马上抽身出来了。 第三个也是被吓得心惊肉跳，因为农夫又说了声："革里特，这是第三个。"第四个端着一个盖着盖子的盘子，财主请大夫显示一下他的才能，猜猜盖子底下是什么。 盘子里装的是螃蟹。 大夫盯着盘子看，可是实在不知说什么好，他哀叹道："唉，可怜的螃蟹呀。"财主一听就大喊："太棒啦！他知道里面是什么，他一定也知道钱在哪儿！"
看到这一切，仆人们的神色格外紧张，他们暗示大夫能不能出去一小会儿。 于是他就出去了，四个仆人都坦白说是他们偷了钱，并且许诺如果他不揭发他们，他们愿意将钱还回而且给他一大笔钱作为酬谢，否则他们会被绞死。 他们带他到了藏钱的地方。 他胸有成竹地回到大厅，在桌旁落座后说道："我的老爷，现在我要从我的书中查找藏金子的地方。"这时，第五个仆人爬进壁炉里想听听大夫还知道些什么。 可是大夫坐着一动不动，打开他的入门书，将书页来回翻着，寻找那只公鸡。 由于一时找不着，他就说："我知道你就在那儿，所以你最好是自己出来！"那位在壁炉里的老兄误认为大夫是指他，真是惊恐万分，一下子跳了出来，使劲嚷："那个人真是神掐妙算，无所不知！"这时万事通大夫告诉了财主藏钱的地方，却没有告诉他是谁偷的，结果双方都给了他酬金，他也由此成了名人。
There was once on a time a poor peasant called Crabb, who drove with two oxen a load of wood to the town, and sold it to a doctor for two thalers. When the money was being counted out to him, it so happened that the doctor was sitting at table, and when the peasant saw how daintily he ate and drank, his heart desired what he saw, and he would willingly have been a doctor too. So he remained standing a while, and at length inquired if he too could not be a doctor. "Oh, yes," said the doctor, "that is soon managed." - "What must I do?" asked the peasant. "In the first place buy thyself an A B C book of the kind which has a cock on the frontispiece: in the second, turn thy cart and thy two oxen into money, and get thyself some clothes, and whatsoever else pertains to medicine; thirdly, have a sign painted for thyself with the words, "I am Doctor Knowall," and have that nailed up above thy house-door." The peasant did everything that he had been told to do. When he had doctored people awhile, but not long, a rich and great lord had some money stolen. Then he was told about Doctor Knowall who lived in such and such a village, and must know what had become of the money. So the lord had the horses put in his carriage, drove out to the village, and asked Crabb if he were Doctor Knowall? Yes, he was, he said. Then he was to go with him and bring back the stolen money. "Oh, yes, but Grethe, my wife, must go too." The lord was willing and let both of them have a seat in the carriage, and they all drove away together. When they came to the nobleman's castle, the table was spread, and Crabb was told to sit down and eat. "Yes, but my wife, Grethe, too," said he, and he seated himself with her at the table. And when the first servant came with a dish of delicate fare, the peasant nudged his wife, and said, "Grethe, that was the first," meaning that was the servant who brought the first dish. The servant, however, thought he intended by that to say, "That is the first thief," and as he actually was so, he was terrified, and said to his comrade outside, "The doctor knows all: we shall fare ill, he said I was the first." The second did not want to go in at all, but was forced. So when he went in with his dish, the peasant nudged his wife, and said, "Grethe, that is the second." This servant was just as much alarmed, and he got out. The third did not fare better, for the peasant again said, "Grethe, that is the third." The fourth had to carry in a dish that was covered, and the lord told the doctor that he was to show his skill, and guess what was beneath the cover. The doctor looked at the dish, had no idea what to say, and cried, "Ah, poor Crabb." When the lord heard that, he cried, "There! he knows it, he knows who has the money!"
On this the servants looked terribly uneasy, and made a sign to the doctor that they wished him to step outside for a moment. When therefore he went out, all four of them confessed to him that they had stolen the money, and said that they would willingly restore it and give him a heavy sum into the bargain, if he would not denounce them, for if he did they would be hanged. They led him to the spot where the money was concealed. With this the doctor was satisfied, and returned to the hall, sat down to the table, and said, "My lord, now will I search in my book where the gold is hidden." The fifth servant, however, crept into the stove to hear if the doctor knew still more. The Doctor, however, sat still and opened his A B C book, turned the pages backwards and forwards, and looked for the cock. As he could not find it immediately he said, "I know you are there, so you had better show yourself." Then the fellow in the stove thought that the doctor meant him, and full of terror, sprang out, crying, "That man knows everything!" Then Dr. Knowall showed the count where the money was, but did not say who had stolen it, and received from both sides much money in reward, and became a renowned man.