比尔·盖茨在哈佛所学的专业是什么？

谢邀。这个问题问法不对。

1. 熟悉美国本科学制的会知道美国大学学制跟我国不同。我国特点是按系招生，招到后编班，某些不能适应的转系。美国特点是按校招生，学校推荐study plan，最后按照你修的课来进入各个不同的degree track。所以除非想毕业，否则不会去操心degree track。

用google搜索bill gates havard "study plan"，可以看到搜得到的结果里面基本都是照抄这一句：

Gates did not have a definite study plan while a student at Harvard[38] and spent a lot of time using the school's computers.

盖茨在操心毕业学位之前，在1974年夏天就去了Honeywell，后来创业去了。他根本都没有到操心毕业的时候。

我个人的看法是，盖茨既然大二上就解决了计算机方向一个顶级问题（见下）

In his sophomore year, Gates devised an algorithm for pancake sorting as a solution to one of a series of unsolved problems[35] presented in a combinatorics class by Harry Lewis, one of his professors. Gates's solution held the record as the fastest version for over thirty years;[35][36] its successor is faster by only one percent.[35] His solution was later formalized in a published paper in collaboration with Harvard computer scientist Christos Papadimitriou.[37]

当时此人已经有高年级博士生的科研能力，本科学位对他来说根本是浪费时间。所以除非他真的不想走科研或创业这条路，否则他根本没必要费神在拿什么学位上。

2. 说盖茨本科是法律专业是个广泛的误解。首先，美国本科是没有法律学士学位的，自然也没有本科法律专业。

Bachelor of Laws
The Bachelor of Laws (Latin: Legum Baccalaureus) or LL.B. is an undergraduate, or bachelor, degree in law (or a first professional degree in law, depending on jurisdiction) originating in England and offered in most common law jurisdictions.[1]
The United States is the only common law country that no longer offers the LL.B. While the LL.B. was conferred until 1971 at Yale University, since that time, all universities in the United States have awarded the professional doctorate J.D.,[2][3] which then became the generally standardized degree in most states for the necessary bar exam prior to practice of law.[4]

盖茨1973年进哈佛，自然是不可能读得到本科法律专业。

3. 说盖茨读法律的可能是误解下面这一句：

He enrolled at Harvard College in the fall of 1973 intending to get a pre-law degree,[19] but did not have a definite study plan.[20]

这是wikipedia一个较老的版本。pre-law degree确实看着像某种法学学位，但是这个词在wikipedia的解释是这样的：

Pre-law

In the United States, pre-law refers to any course of study taken by an undergraduate in preparation for study at a law school.

The American Bar Association requires law schools that it approves to require at least a bachelor's degree for North American students for admission. But no specific degree or major is considered "pre-law";[1] unlike pre-med, an undergraduate student is not required to take a set of prerequisites in order to get into law school. Therefore, universities lack an official "pre-law" concentration.

就是说pre-law不是一种学位。只要有任何一种本科学位就可以申请法学博士项目，此时你的本科学位称为pre-law。

4. 那么为什么说盖茨想拿一个prelaw呢？93年Smithsonian对盖茨的访谈里面关于上学的问答是这样的：

Interview with Bill GatesCollege Plans

DA: We are going to talk a little bit about your transition into Harvard before you got to the Altair. You mentioned that even though you worked in computing, that it wasn't your goal when you went to college. Do you want to say what your goal was?

BG: That's right. I finished up at TRW, went back, and graduated from Lakeside School. I picked, out of the schools I'd been accepted to, to go back to Harvard. They seemed to have a lot of different things. I knew that if I wanted to be a Lawyer or a Mathematician, Harvard had good courses for these things.

盖茨在此处的意思是说，当时他还拿不定主意选择什么职业，而做个律师（像他父亲）或者做个数学家（见上，盖茨数学很好）是两个明显的选项。

或许他父亲曾经表示过让他学法律的意愿，或许没有，这次访谈里没有说。我个人的猜测是没有，因为从盖茨的自述里看不出他父母对他的发展有任何限制，倒是鼓励和支持居多。从

访谈中可以看出，从盖茨12岁开始就是这样了。

综上，盖茨在哈佛，最准确的描述是没有专业，但是修了一堆显然后来对他发展很有用的课。

比尔盖茨进的是Harvard College，一开始对自己的数学天赋很自信想pure math的，不过后来的degree track是Applied Math。因为当时哈佛的计算机faculty是和应用数学在一起的，没有独立的计算机系，重要的证据就是他上过哈佛的Math55，然后因为被某个同学虐了，一怒之下放弃pure math，学了Applied Math。那个年代计算机科学和数学基本混在一起，他花了相当多的时间学计算机的课程，用今天的观点来看，可能是应用数学和计算机科学的双学位比较恰当吧。

顺带一提，当年Math55虐他的那个同学后来反倒成了华尔街上的一个成功的律师。。。