The question, which came from 'Falconer', is as follows:
It's an interesting question, because the order in which I actually read them isn't the order that I would now read them in if I were coming to them fresh.
My own experience was to read the Ransom trilogy in order of their composition and publication: OUT OF THE SILENT PLANET (which remains my favorite of all Lewis's novels), then PERELANDRA (Tolkien's favorite of Lewis's series, but while I think it more ambitious than OSP I find it far inferior in achievement), then THAT HIDEOUS STRENGTH (which I privately call 'That Hideous Novel', which pretty much sums up my opinion of that book). Several years later I learned of the publication a year or two earlier of THE DARK TOWER, which I then hunted down in the Fayetteville public library and read. And of course I read THE LOST ROAD (which I think is underrated) and THE NOTION CLUB PAPERS (another underrated work) as soon as possible -- one of which I actually got to see slightly before publication.
This is of course, partly by happenstance, simply the order of publication. If you were to read then in internal chronological order, it'd go more like this: start with THE LOST ROAD, including the notes and outlines. Next would come OUT OF THE SILENT PLANET, then move on to THE DARK TOWER (placing it by its internal chronology). Then I'd revert back to order of composition with PERELANDRA. Then comes THAT HIDEOUS STRENGTH, followed by THE NOTION CLUB PAPERS, again with the later's associated outlines and notes and ancillary material.
All this presupposes that THE DARK TOWER is a genuine Lewis work, which I believe has been established beyond any reasonable doubt, and also that it was written circa 1944-45 (as I've argued in print), not circa 1938 (as Walter Hooper believed).
My own preferred order to re-read it now, I think, wd be along the lines of LOST ROAD, then OSP, then PERELANDRA and THAT HIDEOUS STRENGTH, then THE DARK TOWER, ending up with THE NOTION CLUB --that is, pretty much the order of composition, so far as we can determine it.
One thing that might help you decide which order might be best for you: in what order do you read the Narnia books? Publication order? Internal chronology? I hope to never have to read them again, but if I do I'm pretty sure I'll go by publication order again, because that's my default when reading a series: I like to see an author's mind at work as he or she explores possibilities that come to light over the course of a series.
And of course I've long been an advocate of the school of thought that you should be able to read the books in a series in any order,* so in my heart of hearts I'd say the sequence doesn't matter.
Hope this helps.
--the latest Flavia de Luce novel (just finished);
--The Last Apprentice bk four (resumed)
*I'll often start a book in the middle, read to the end, then go back to the beginning and read to my starting point. I find this works especially well with biographies and not v. well with mysteries.