I have spent a lot of time looking for a ‘booklet’, ‘book’, etc. on the duties of a deacon.
As to the booklet about deacons, that would be a good topic to cover in a second Bible Course on the Church, but I do not recall seeing a book out there just on deacons and their responsibilities. We know why they were first chosen, so the pastor(s) could continue to center on prayer and the ministry of the Word, without getting too bogged down in daily tasks around the church. Acts 6:1-4 says, “And in those days, when the number of the disciples was multiplied, there arose a murmuring of the Grecians against the Hebrews, because their widows were neglected in the daily ministration. Then the twelve called the multitude of the disciples unto them, and said, It is not reason that we should leave the word of God, and serve tables. Wherefore, brethren, look ye out among you seven men of honest report, full of the Holy Ghost and wisdom, whom we may appoint over this business. But we will give ourselves continually to prayer, and to the ministry of the word.” They were to be chosen by the congregation (“Wherefore, brethren, look ye out among you seven men of honest report, full of the Holy Ghost and wisdom”), and then to be given their duties by the pastor(s) (“whom we may appoint over this business”).
There are so many churches that do not pattern their deacons after the Bible, but after our government. They make deacons more like congressmen and senators (not as hands-on doing the work as the Bible teaches, but as legislators who make the rules and tell everyone else what to do). That is why many churches call the deacons a “Board — the Deacon Board.” They are like the boards who run companies, having the final say on this and that.
In that fashion, the deacons in many churches become more like the Pharisees, than like the deacons in the Bible. Matthew 23:1-11 says, “Then spake Jesus to the multitude, and to his disciples, Saying, The scribes and the Pharisees sit in Moses’ seat: All therefore whatsoever they bid you observe, that observe and do; but do not ye after their works: for they say, and do not. For they bind heavy burdens and grievous to be borne, and lay them on men’s shoulders; but they themselves will not move them with one of their fingers. But all their works they do for to be seen of men: they make broad their phylacteries, and enlarge the borders of their garments, And love the uppermost rooms at feasts, and the chief seats in the synagogues, And greetings in the markets, and to be called of men, Rabbi, Rabbi. But be not ye called Rabbi: for one is your Master, even Christ; and all ye are brethren. And call no man your father upon the earth: for one is your Father, which is in heaven. Neither be ye called masters: for one is your Master, even Christ. But he that is greatest among you shall be your servant.”
A person will look long and hard to find a church with a Scriptural setup for deacons. And then, long and hard to find some ambitious deacons who are taking their position seriously. Many take the position, only to be more occupied with earthly matters, and fail to faithfully fulfill their duties as a deacon. I Timothy 3:13 says, “For they that have used the office of a deacon well purchase to themselves a good degree, and great boldness in the faith which is in Christ Jesus.”