Another reason you will want several books for reference is accuracy. Names, relations, even stories differ book to book. This is further changed by the author's preferences and her or his knowledge and ability to present the material from an objective, precise standpoint. Anyone familiar with foreign literature will know the difference between a good translation and an inferior one. Luckily, the world has a standardized King James Edition of the Bible, one that is eloquent and moving.
Translations are a subjective thing, both for the translator and the reader.
The translator uses English equivalents to the foreign words as best as possible without going too far outside of the way WE speak. This is important because authors usually pick one of these and stick with it. Secondly, structure is important for legibility and accuracy. Many old poetic forms create difficulties for the translator, who suddenly must stop thinking like a translator and think like a poet. Presentation, the third reason, is another subjective thing.