Logic - the key to true understanding

  In the quest for knowledge, there is one concept that stands as the most important.  Without it, truth would cease to exist, ideas would have no meaning and character would vanish along with any moral law.  The past few months I've been taking an in depth look at logic using a curriculum written by Daniel Valles.
  The Art of Logic focuses on building concepts about logic, starting with the simplest and working toward the more difficult.  The series of 41 lessons uses a workbook and each lesson has it's own video.  One of the advantages of this course is the fact that much of the material refers to scripture using the KJV.
  Much of the understanding of logic that Valles comes to is derived from Isaac Watts book Logic. 

  I intend to continue to study logic beyond this course and Isaac Watts' book.  Some of my more recent thoughts have come out of this study, such as a theory for a creative artificial intelligence engine which hopefully I can talk about in a future post.
  Know of any good sources for the study of logic?  Please comment!