For a consulting assignment last year I had to survey the field of textbase software, text/wordprocessing indexing software and document imaging software. At that time, the best and most flexible INDEXER of existing files was Isys, and the best (but simultaneously most annoying) textbase where you could throw in anything and index it in a lot of genuinely useful ways was Ask Sam. ZyIndex came in someplace in between, and a shareware thing called dTsearch wasn't bad (esp. because it was shareware and you could try it out for free). Anybody who wants to know more about any of these or the ones not mentioned here, feel free to email me.