The HarperCollins Concise Guide to World Religion: The A-to-Z Encyclopedia of All the Major Religious Traditions
I found a nicely priced second hand version of the Dutch translation of Dictionnaire Des Religions book (1990) which became Wereldreligies In Kaart Gebracht. I believe it is the first book of the Romenian scholar Mircea Eliade (1907-1986) that I read. It is -so to say- a summery of the massive result of Eliades lifelong investigation of all the worlds religions. A book of not even 400 pages speaking of (almost?) every religion that you can think of, old or new, big or small. African religions to gnostic religions, mystery-religions, Eastern religions, name it, and this duo has a chapter or at least a paragraph about it. The book is divided in 33 groups which are each split up in paragraphs. There is a massive index referring to the paragraphs. Everything is -as Eliade wanted- put to readable (Eliade wanted something for the general public) that it really became “a novel of the worlds religions” as the preface puts it. So just try to lay your hands on this standard-work as well.
Read quotes of Eliade here.