Discussion: What makes a book 'worthy' and 'helpful'?

 So I've been skimming 25 Books Every Christian Should Read. And even though my semi-review has posted, I think I'll keep skimming. (After all, my review would not have been "reviewing" each and every book on the list anyway.) One thing in the introduction bothered me or agitated me. Two statements actually. One made by the authors of this book, the editorial team:

Our belief is that it is best for books to be in the canon for a while before we can clearly evaluate their worth and helpfulness.

The second made by C.S. Lewis:

"A new book is still on its trial and the amateur is not in a position to judge it."

Are either of these statements true? And if you do find them to be true, are they always, always true or are they just generally-speaking true?

So here are my question(s) for you:

• How can a book--any Christian book--be evaluated for "worth" and "helpfulness"?
• Who can do the evaluating or judging of the book's "worth" and "helpfulness"?
• What are the standards for judging a book? How is "worth" and "helpfulness" to be determined? Are these standards, personal standards? Or are the standards taken from the Bible? Are we judging a book based on its persuasiveness--if it sounds good, feels good? Or are we judging a book based on its soundness, examining it in light of Scripture? Or is "worth" and "helpfulness" determined by committee, by any committee, by any majority consensus?
• If the Bible, the Scripture, is the standard of excellence, of worth, of helpfulness, then why does time matter at all? Wouldn't the only consideration of a book's "worth" and "helpfulness" be if the book says true things about God, true things about Jesus, true things about the Holy Spirit, true things about the gospel, true things about sin, true things about our relationship with God, true things about salvation--the cross and resurrection, true things about prayer, true things about worship? true things about heaven AND hell? 
• If EVERYTHING we need to know of the Christian life is in the Bible--found within the pages between Genesis and Revelation--why would we ever use any other standard? Shouldn't all books--Christian or secular--be read in light of Scripture?
• What makes a professional, a professional? And what makes an amateur, an amateur?
• Is a casual reader--like you and me, supposedly--just an amateur? or always an amateur? 
• Isn't any student of the Word of God, any reader who is devoted to reading, studying, and meditating on the Word of God, capable if not responsible for "judging" books new or old? 
• Isn't a new book that is rich in gospel-truth, deeply rooted or grounded in the Bible a better reading choice for most--if not all--than some old "classic" that is more prone to mysticism and touchy-feely spirituality where what matters is not what the Bible says or doesn't say but how the author feels about God, what the author feels to be true about God?, how the author has come to relate to God? 
• Shouldn't the content of the book alone be the main thing? 

© Becky Laney of Operation Actually Read Bible