Turning to the entries themselves, I thought I'd look first at books I know have some complexity. I went to the entries for Lord Dunsany. Yes, they are presented chronologically (another Joshi oddity), not alphabetically, so The Sword of Welleran and Other Stories (1908), item 924 on page 129, is four pages before The Sword of Welleran and Other Tales of Enchantment (1954), a different selection of stories, item 940 page 133. If you don't already know the dates for Dunsany's collections, there is an index at the back of the book, so you can waste time flipping back and forth. (This extra-labor idiocy is a common feature of Joshi's "bibliographies".) But the Dunsany I came to look for first is The Last Book of Wonder, the US title, or Tales of Wonder, the UK title, and of course Joshi doesn't tell you that there is a different (longer) "Preface" in the US edition than in the UK edition, nor does he tell you that the tales are presented in a different order in each volume. Joshi lists some reprint editions, including print-on-demand ones up through 2009, but gives no details of which version is reprinted. As is common with Joshi's checklists, any details (and context) are ignored in order to fit whatever rote format Joshi had previously decided upon. The usefulness of this book decreases the more you look at it.
I then thought I'd check some of the books I edited. The expanded edition of G. Ranger Wormser's The Scarecrow and Other Stories (2001) is present. My Adrift on the Haunted Seas: The Best Short Stories of William Hope Hodgson (2005) is attributed to "Douglas Anderson" (I never omit my middle initial, simply because there are other Douglas Andersons who write and publish). I also edited the fifth volume of the Night Shade Hodgson series, The Dream of X and Other Fantastic Visions (2007), but Joshi attributes it to Jeremy Lassen. Joshi mentions Devil's Drum (1933), by Vivian Meik, but not my expanded version, as it came out from Medusa Press in 2011, just beyond Joshi's arbitrary cut-off point. There are similar issues with other books I was involved with, but I will move on.
For Mark Valentine, four books and one booklet are listed, again just covering through 2010, but Joshi has left out The Nightfarers (Ex Occidente, 2009). Reggie Oliver's first five collections are duly listed. R.B. Russell's first two collections are listed, but not any by Rosalie Parker (The Old Knowledge and Other Strange Tales, 2010, should be here). Nor is Brian J. Showers's The Bleeding Horse and Other Ghost Stories (2008) to be found. I mention these writers to note that most of them have published several other collections since Joshi's cut-off point of twelve years ago. What use is such a listing of only the stories (no introductions, etc.) of their earliest collections?
Even when the information appears to distinguish the differing contents of the various editions, it is often incomplete. For example, with Nigel Kneale's Tomato Cain and Other Stories, Joshi lists three editions, 1949 (UK), 1950 (US) and 1961 (UK), and notes the differences in content between the 1949 and 1950 edition, but not the further differences in the 1961 UK paperback. (Of course, last year's reprint which includes all of Kneale's stories is unmentioned.)
So it goes. This oversized book, with 428 pages indexing the collections, a 39-page "Index of Names" and 270+ pages of an "Index to Story Titles," totals 741 pages. It is a disappointing production, and one of very limited usefulness. The sad truth is that with a bit more work this volume could have been valuable.