'Edisons' is NOT officially related to TWoTW, but is, possibly, the first sequel. A few sequels to the work have been offered since, including my own novel. But I've ultimately (as one who wrote!) found that it's ground best not stepped on for the moment.
There is an early 'Pearsons' magazine version (ie. the first draft) of the book available online. Alas, my old PC died in transit, along with the favourites links to things such as this that I had.
Give me a little time and I will find it for you.
Le Grand Fromage! (Le New Generation!)