In the first year of his reign: this is a repetition of the information given in the previous verse, but it seems to fit better in this context than earlier.
I, Daniel: as in 8.15, 27, this form seems to mark a new section in the story. Compare also 7.15, 28; 8.1.
Perceived: the verb used here usually means “understand,” but this meaning is hardly suitable to the present context. New American Bible has attempted to adjust to the context by translating “tried to understand,” but it is probably better to take the verb in the sense of “was studying” (Good News Translation, New Jerusalem Bible) or “carefully considering.” There is no problem in understanding the number of years, since this is clearly stated in Jer 25.11-12; 29.10.
The books: the term is used here in the technical sense of the holy books known to Daniel—including the book of the prophet Jeremiah. For this reason it is legitimate to translate “the Scriptures” (An American Translation, Revised English Bible, New American Bible, and New International Version).
The word of the LORD to Jeremiah: it will be more natural in some languages to say “what the LORD had revealed to Jeremiah” or something similar.
The prophet: while it is true that the prophets of the Old Testament did sometimes foretell the future, this is not the primary focus of the term. What is more important about the function of the prophets is that they communicated to people in behalf of God. Many languages have special terms to refer to the spokesman or herald of a chief. And it is often possible to use this term in an expression meaning “herald (or spokesman) for God” or “one who proclaims God’s message.” In other languages it is possible to say “a person sent by God.” But translators are advised to avoid the idea of “foreteller of the future.”
The end of the desolations of Jerusalem: the writer seems to be suggesting that the years of devastation were fulfilling some purpose and had to be completed before any rebuilding could take place. Seventy years was considered the divinely established period (see 2 Chr 36.21). Translators should not, however, give the impression of seventy consecutive years of acts of destruction. Rather, this period should be understood as the time during which Jerusalem remained in a desolate state. Revised English Bible speaks of “seventy years which … were to pass while Jerusalem lay in ruins.”
Quoted with permission from Péter-Contesse, René & Ellington, John. A Handbook on Daniel. (UBS Helps for Translators). New York: UBS, 1994. For this and other handbooks for translators see here .