What is the Canon and how does it pertain to Bible Study?

The Canon is the measuring rod which people who were guided by the Holy Spirit were able to recognize what books are truly divinely inspired and separate those from good stories, history, and mixtures SSgt Robert Marx
The council at Nicea [2], Constantinople [3], Chalcedon and Ephesus helped the early church to be able to "see" through the controversies which helped later apologists gain tools to deal with false doctrines and their purveyors.
http://www.bible.ca/b-canon-councils-synods-canons.htm

The canon of Scripture refers simply to those ancient writings accepted by Christians as authoritative or speaking with apostolic authority. The Lord Jesus Christ delegated His authority to 12 men who were individually commissioned, present throughout His earthly ministry, and eye witnesses of His resurrection which serves as God’s authentication that Jesus is divine and Israel’s messiah. These same apostles later wrote several decades after the events transpired a holy transcription either directly or through the pen of a transcriber, writing either biographical data about Jesus and subsequent apostolic activity, epistles of direction for the fledging church, or end time prophecy concerning the coming “Day of the LORD” motif that also occupied earlier Old Testament prophets such as Daniel, Ezekiel, and Zechariah.
The Jewish community had cemented their own holy writings, especially the instruction from the covenantal mediator Moses, by the time the church appeared. Their time was spent arguing about what books to include in forming the Septuagint which was the first authorized translation of Scripture from the Hebrew & Aramaic and into Hellenistic Greek. The time of Alexander (the fourth century BC) with its hegemonic control over the kingdoms of the middle and far east alongside the diaspora of the Jewish communities due to the Babylonian Empire meant that Jewish communities lost their Hebrew language but many if not most spoke Greek as the primary or native language. The times of the first century BC saw a temporarily independent Jewish state in its homeland plus sizable Jewish diaspora communities with a primary one being in Alexandria Egypt and so the Septuagint was not only completed but was recognized as an excellent translation. The libraries in Alexandria contained many Hebrew copies of Scripture which have been lost to our day. The Jewish scholars presented all of what is now known as the Old Testament plus a few other works now known as the Apocrypha in the Septuagint which also is known as LXX, after the 70 Jewish translators. A conference at Jamnia at the end of the first century AD by Jewish scholars recognized as Scripture only those books as now contained in our Old Testament.
The churches established by the apostles circulated among themselves scrolls that had been delivered by those same apostles and continued the work of hand transcription of the sacred text. The church recognized as Scripture only those works completed by an apostle or the associate of apostles, the works recognized as Scripture by the individual church plants in their respective communities plus the Church father’s recognition, works that had the style or authority of Scripture by clearly stating its divine origin, and only those works that carried the divine stamp by meshing completely within the doctrines handed down by the apostles. The Emperor Constantine in the fourth century AD placed the Christian church into legality by allowing it to function in the Empire and then Emperors Theodosius & Gratian made Christianity the official religion of the Empire. It was under the revolutionary changes to daily life where church men went from being state outlaws to officials of the state that various ecumenical councils of the entire Church met in order to codify the official dogma. The Third Council of Carthage in AD 397 adopted the canon as the 27 recognized New Testament books. Canonization does not make a work a part of the Bible rather it recognizes the work that God had previously inspired.
The time of the Reformation of 500 years ago recognized that the Church universal had a faulty understanding of its role, makeup, and polity. The reformers proclaimed that Scripture alone bears the authority in propagating doctrine. It is faith alone in Christ alone through grace alone that salvation is wrought and is taught in Scripture alone in its fullness. The lesson learned is that Christians must abide in the Vine of Jesus Christ by abiding with Him in the light of His word which has been passed down by holy men of God in the Bible. The holy Scriptures cannot be tampered with, altered in their constituency, or amended by any act of humanity. We trust that God inspired His word, allowed for its accurate transmission throughout history, and even today protects it against change.