All of the 24 commentaries on 1 Peter that I have here in my study interpret 1 Peter 3:21 to be speaking of water baptism rather than some sort of Spirit baptism. I have in my personal library only 37 books specifically on the Holy Spirit, but two of them are excellent:
Swete, Henry Barclay. The Holy Spirit in the New Testament. London: Macmillan and Company, 1910. (417 pages). In addition to the New Testament, Swete covers “SOME EARLY CHRISTIAN UNECONOMICAL GOSPELS, ACTS, AND APOCALYPSES.” He assumes that the readers of the book are fluent in Greek and Latin, but he provides a translation for Hebrew words. This book was the result of many years of intense scholarship and deserves a place in the personal library every English speaking Christian who seriously desires to know and understand what the New Testament says about the Holy Spirit.
Bruner, Frederick Dale. A Theology of the Holy Spirit. Grand Rapids: William B. Eerdmans/Publisher. 1970. (390 pages). This is another very well researched scholarly work with an extensive bibliography (34) pages. Foreign words are translated. Very much of the book is devoted to Pentecostalism and although Bruner is not Pentecostal he has an excellent understanding of it and treats it fairly and respectfully.
I need, however, to mention one more of the 37 books.
Torrey, R. A. The Person and Work of the Holy Spirit. First published in 1910. Torrey had an excellent education but he is not primarily known for his scholarship but for his success as an evangelist, educator, and writer. This book is much more brief than the other two, but it is packed full of spiritual insights making the reading of it to be highly recommended.