Edition 2 of the History of Programming According to Mantis:
In the beginning, all programming was machine language. When you programmed you had a table in your hand that said that "101110" was move data, "1110110" was add, etc. (Actually it was more complicated than this because there were different types of move commands, different types of add commands, etc). It was complicated and tedious work, and nearly all of it was in binary or octal (although there were decimal computers too... many thought that decimal computers were so much easier that they would make the faster binary computers obsolete. Wrong!). This was the first generation of programming languages.
Along came a programmer who said, "hey, this is all really tedious and error prone. Computers are good at solving tedious and error prone things. Let's wrote a computer program to help us write computer programs." She (I believe it was a woman) wrote this and all the other programmers smacked themselves in the head and said "Why didn't I think of that?" Thus was born the second generation of computer languages, assembly languages and other languages that were little more than a direct translation from human-readable codes like "MOV 103, 15" to machine-readable codes. Every computer had its own assembly language, so a program written for one computer couldn't be moved to another.
Then some guy came along and realized that we could do a lot more than that. That we could make a programming language that was specifically designed for humans to use. Something easy, something that you could really sit down and work with. Fortran was born. Fortran was the very first true computer language. Its inventors expected other computer makers to make similar human-friendly languages for their computers but they didn't. They created copies of Fortran instead. It became the first cross-platform language. By modern standards, it stunk, but at the time it was great. Computer scientists used what they learned from Fortran and made many other languages. One, "Algol" was specifically designed for computer science. It was the first real structured programming language. C, Ada, and Pascal decended from Algol. Basic decended from Fortran. Visual Basic is somewhat a cross between Pascal and Basic. These are third generation programming languages.
There was a category called "fourth generation languages," or so-called "expert systems" and declarative programming. But they all died when programmers realized they sucked. (Okay, a wee bit of editorializing here. Sorry. Let me try again.) They fell into disuse when programmers realized they weren't living up to their hype (better?).
Object oriented programming started with Simula and SmallTalk. Simula never really went anywhere, but SmallTalk was a great little language, but it wasn't destined to be the langauge that brought OOP to the masses. That title went to C++, which started as C with object oriented extensions. The idea of Object Oriented Programming is that instead of working directly with the data, why not teach the data to work with itself? Instead of thinking of data and code seperately, why not think of data as something that has information and state as well as functions. C++ spawned Java and C#. Visual Basic gained objects. These days OO programming is the big thing.
It's hard to credit any one person with any one "generation" of programming languages. This is, in part, because it's hard to credit any one language with bridging that gap. But if you had to choose, I'd say Fortran was the first 2nd generation langauge and Smalltalk was the first OO language. John W. Backus created Fortran, and Alan Kay created Smalltalk. Both had lots of help.
Hope this helps.