So, why all the fuss about Alan Turing having invented a machine that is the grand-daddy of all computers, past, present and future? Well, it's a bit like Einstein's E = mC2. This simple equation was the key to understanding that matter can be transformed into energy. But, between understanding the equation and being able to obtain energy from a nuclear reactor, a lot of hard work needs to be carried out. You might say poetically that the Turing Machine defines the "soul" of any imaginable computer in the real world. But, to move from the abstract "soul" to a real "flesh and blood" computer, you have to envisage a huge amount of design, engineering and programming... of both a hardware and a software kind.
Funnily enough, although the Turing Machine can indeed carry out any imaginable task that might be performed by modern computers, it's greatest interest was that it enabled Turing and other logicians to discover that certain tasks could never be carried out by any imaginable computer whatsoever. For example, it is impossible for a computer to determine beforehand, when faced with certain algorithms, that it will indeed be able to reach the intended end of the algorithm and provide an answer. In this way, the Turing Machine appeared on the scene as a mechanical variant of the themes of incompleteness and undecidability elucidated mathematically by Kurt Gödel (seen in the following photo alongside Albert Einstein):
Getting back to Turing, his most concrete claim to fame was surely the wizard-level code-breaking operations that he performed for the British government during World War II, at Bletchley Park.
He was a practicing homosexual at a time in the UK when relationships of this kind were branded as criminal. The poor man, suffering no doubt from a form of autism (Asperger Syndrome) that made him socially awkward, was obliged to undergo ignominious chemical castration. In June 1954, a fortnight before his 42nd birthday, Turing was found dead in his laboratory, poisoned by cyanide, and clutching a half-eaten apple.