"Terry was, of course, by no means alone in spending some of his young years regarding The Lord of the Rings as right up there among the greatest achievements of humanity. But for Terry it seems to have been not just about what the book itself was, but also about what that book opened up beyond itself, the way it sent him to whole other thus far untravelled regions of the library: the mythology section, the ancient history shelves, the history shelves, the archaeology shelves . . . It was an earthquake that sent cracks running off across the surface in multiple directions."
Different folk's experiences differ,* but to move from discovering Tolkien into searching for 'more like this' is another hallmark of JRRT's impact of his audience. It was certainly my experience. I read Alexander and Le Guin and Eddison as I shifted from science fiction to fantasy because I was looking for 'more books like Tolkien'. Tolkien also lead me to BEOWULF and SIR GAWAIN and THE FAERIE QUEENE, Grahame and Carroll, and so much more (my reading list is well over four thousand books in the last forty-seven years, and counting).
I also read his fellow inklings: Christopher (the first book I read by Christopher being THE SAGA OF KING HEIDREK THE WISE) and CSL and Barfield and Ch Wms. Not to mention books about these authors and their works, starting with Ready and Carter and Kocher.
Perhaps we shd look more into Tolkien's extraordinary grip on those of his readers he captures.
--current reading: Pratchett biography (nearing the end)
*see for example Paul W's comment on my preceding post