Alexander Wilder was and American physician and Neoplatonist scholar. During the years 1877-1880 he served as a Vice President, along with John A. Weisse, of the Theosophical Society, under President Abner Doubleday. After that, he was a member of the General Council of the Theosophical Society.
Involvement with Isis Unveiled
When the work was ready, we submitted it to Professor Alexander Wilder, the well-known scholar and Platonist of New York, who after reading the matter, recommended it to Mr. Bouton for publication. Next to Colonel Olcott, it is Professor Wilder who did the most for me. It is he who made the excellent Index, who corrected the Greek, Latin, and Hebrew words, suggested quotations and wrote the greater part of the Introduction 'Before the Veil.' If this was not acknowledged in the work, the fault is not mine, but because it was Dr. Wilder's express wish that his name should not appear except in footnotes. I have never made a secret of it, and every one of my numerous acquaintances in New York knew it." 
As Boris de Zirkoff pointed out,
"Many statements by HPB, particularly in Isis Unveiled, the Key and the Glossary are taken from Dr. Alexander Wilder's small booklet: New Platonism and Alchemy, Albany, N.Y., 1869.
Dr. Wilder wrote many articles about medicine and Theosophy. The Union Index of Theosophical Periodicals lists [ over 60 articles by or about Wilder].
Some of Wilder's works are available online:
- "Wilder - Collected Articles". Compiled by Mark Jaqua. Available at Scribd for a fee.
- "Later Platonists - Alexander Wilder". Compiled by Mark Jaqua. Available at Scribd for a fee.
- "How "Isis Unveiled" Was Written". The Word 7.2 (May 1908). Available at Theosophical University Press Online.
- "New Platonism and Alchemy" Albany, NY: Weed, Parsons and Company, 1869. Available at Theosophy NW website.
- "The Ganglionic Nervous System," Intelligence (February and March, 1898). Wilder posited that "this system preceded the cerebro-spinal nervous system and is the germ of everything that is afterward developed." He claimed "it is the first thing created in our bodies, the last which is palsied by death."
He served as editor of these works:
- Clarke, Hyde, and C. Staniland Wake. Serpent and Siva Worship.
- Knight, Richard Payne. Ancient Art and Mythology. Wilder also contributed an introduction, notes, and and index.
- Westropp, Hodder M. and C. Staniland Wake. Ancient Symbol Worship. Wilder contributed an introduction, notes, and an appendix.
- Taylor, Thomas. Eleusinian and Bacchic Mysteries: A Dissertation , The.
- Kimberley Nichols, "The Eclectic Life of Alexander Wilder: Alchemical Generals, Isis Unveiled, and Early American Holistic Medicine", Newtopia Magazine (February 15, 2013). Available at Newtopiamagazine.wordpress.com.
- "Letters from H. P. Blavatsky to Alexander Wilder, M. D.", The Word 7.3 (June 1908). Available at Theosophical University Press Online.
- "The Theosophical Society," The Theosophist 1.8 (May, 1880), 214.
- H. P. Blavatsky, "My Books" in Theories about Reincation and Spirits and My Books (Point Loma, California: Theosophical Publishing Co., 1922), 33-34. Written April 27, 1891.
- Boris de Zirkoff to Armand Courtois. January 18, 1970. Boris de Zirkoff Papers. Records Series 22. Theosophical Society in America Archives.
- Anonymous, "Book Reviews," Mercury 4.7 (March, 1898), 253.
- Anonymous, "Book Reviews," Mercury 4.8 (April, 1898), 288.