I recently wrote a review of the big college guidebooks for Slate magazine | http://www.slate.com/id/2127455/ . I ranked the books on depth, verve, detail and student perspective. I am grateful to readers of this column who responded to my request for advice on which guides they liked best, although when reader opinion clashed with my own, I always went with me.

You can, however, dismantle and reassemble my review to suit your own tastes by adjusting the weights I gave to each factor. And as a reward for all your free advice, I am going to share some of the discoveries that most intrigued, and sometimes bothered, me as I sifted through those nearly 15,000 pages of collegiate marginalia stacked two-feet high on my dining room table:

1. Some of the Profiles Are Actually Paid Ads: Two of the biggest guides, "Peterson's Four-Year Colleges 2006" and the Princeton Review's "Complete Book of Colleges 2006," had large sections reserved for college descriptions that turned out to be written by the colleges themselves, even though that was hard to tell just looking at them. Most of these commercials were well-done, and I am sure beneficial to many readers, but I wish the publishers had made more of an effort to signal their true nature. My own newspaper, I acknowledge, runs glowing accounts of Middle Eastern tourist stops that include copy made to look like news stories, but at least we run the words "Paid Advertisement" on the top of those pages. At least I hope we still do that. Some days I don't get to read the entire paper.

I could not figure out why some colleges bought profiles and other similar schools did not. Pomona College, for instance, had no paid ad in the Peterson's book while the other four Claremont, Calif., colleges did. Pomona College Admissions Dean Bruce Poch told me this had nothing to do with any distaste for self promotion. The previous year, Pomona had paid $3,200 for its ad, plus $340 for a 50-word boldface highlights box that preceded the Pomona entry in the front of the Peterson's book. Poch refused to advertise this time in protest of Peterson's promotion of its online application-essay editing service on its Web site. Poch considers this an invitation to get someone else to write your application essay for you, and he does not want to encourage that by sending Peterson's several thousand dollars.

2. The Guides Should be Arranged by SAT Scores: This will seem contradictory to readers who have suffered through my frequent denunciations of the SAT and ACT tests. I think high school students spend too much time and money preparing for them, and I think they do not adequately reflect what good teachers are trying to teach in high school. I would prefer that colleges use Advanced Placement, International Baccalaureate or SAT subject test results in the college application process, since those exams grow out of actual high school courses.

But it is also clear to me that your SAT or ACT score is a useful sign of which colleges are most likely to accept you. All the guide books provide the average SAT or ACT scores of entering freshmen at each school, and if your score is not at least at the 25th percentile in that group of accepted students, it is probably a waste of time and money for you to apply. (This bit of wisdom does not apply to state champion quarterbacks, published novelists or teenage movie stars.)

If the guide book authors were honest, they would admit that SAT and ACT rule the sorting process--so why don't they arrange all these schools by their average freshman scores? There are terrific colleges with great professors and fine extra curricular opportunities at every level of SAT or ACT achievement -- why not allow us to see at a glance which schools are in our league?

Some guides come close to doing this. They all should give it a try.

3. The Better Written the Guide, the Fewer Schools It Mentions: I suppose this makes sense. The wordsmiths hired to provide the lively sentences and vivid descriptions that distinguish the best guides cannot be expected to be charming and witty for all 4,000 undergraduate institutions in the United States. The guide book companies could hire more writers to carry the load, but that would cut into profits, and put the editors' jobs in jeopardy.

Keep this in mind as you check the college guide shelves at your local bookstore or library or online distributor. The smaller books may seem to be giving you less for your money, but if they cover one or two of the schools you are interested in, they are probably worth a look. You are going to learn more from them about those particular schools than you will from the bigger books.

4. College Professors Don't Exist: I dare you to try to find a big guide book that consistently names and discusses the academic stars whose lectures and seminars and invitations to dinner are among the things you are most likely to remember about that college decades later. Only one of the books I looked at, "Choosing the Right College," did this with any frequency.

5. Community Colleges Don't Exist Either: The people who publish college guides speak often of their "aspirational" nature. That means the families most willing and able to pay $20 to $30 for one of these books are those least likely to encourage a child to go to a community college.

Yet 46 percent of U.S. undergraduates attend one of these two-year schools, and I suspect there are many families who would appreciate help in figuring which ones provide which courses and which services. The only guide I found doing that was the College Board "College Handbook." I am, I confess, one of those "aspirational" parents, and until I saw those pages in the College Board book, I never even considered the fact that this kind of information might be useful.

6. Outdoors? Where's That? We all think we know what the weather is like in the various regions of this great country, but we lack precise information, and none of the guides I looked at provided it. Annual snowfall? Rainfall? Average seasonal temperatures? Few told me anything like that. I was particularly distressed that I could not find the names, phone numbers and green fees of the local golf courses. My college search with one of my sons leaned heavily on what we found at the local links, and on that subject, not even the largest and most detailed of the guides had a clue.