Lets say I want to buy a textbook to augment my current textbook. The new edition is about $90 but an edition that is 15 or 25 years old is about $15. Would the old edition give me crappy, incomplete info or does it depend on the subject (like I know computer science textbooks from 1985 are a bad idea but maybe calculus textbooks are not)? The textbook would just be used to augment what I already know and it is for basic inorganic chemistry and I don’t know if alot of nouveau discoveried have been made in inorganic chemistry in the last 15-25 years. At least not the fundamentals of inorganic chemistry.
Not a science-based answer…
Dealing with music-related texts, often the only significant change was to update the bibliography, and to add to footnotes that new relevant bibliographical information was available. But that is crucial - failing to make use of that newer information could send you down a very misleading path.
My suggestion is to buy the $15 version, and take it into a library and compare it to the newer one - hopefully, it’ll be clear where changes have been made, and you then know when to check against a new version. If it’s not the case, and you really need the new version, you’ve only lost $15 (which you can probably recoup by selling it onto another equally-foolish newbie 
)
Sadly I can’t get it at the library.
We have a university library and a public library. The university library’s copies (2 of them) are checked out. The public library doesn’t carry it and when I asked the public library if I could request an interlibrary loan they said no, not if the university library carries it. Even if its checked out.
So there is no way to check to see if the copy is up to date.
The subject(s) I need help with are things like metallo-ligand bonding, molecular orbitals, Hunds rules and its various applications, crystal field theory, ligand field theory, etc. I don’t know if these subjects have undergone major overhauls in the last 30 years though. The ‘newest’ edition of the textbook i’m referring to was printed in 1995. The 2nd edition was from 1987 and the first edition is from 1976.
I guess one way to check if it’s a major revision would be to look up reviews of the 1995 version in relevant journals. And if there’s few or no reviews, it’d suggest (but not prove) that it’s a minor revision.
(BTW Have you checked out what inter-library loan system is available? Is there a recall system for books checked out (where they have to be then returned within eg. a week)? Plus, complain about a book in (presumably) such demand being checked out on regular loan.)
Textbook copyeditor/proofreader chiming in.
Once the book is in about a fourth or fifth edition, especially in a fairly static field, very few substantive changes are made (at least in the hundred-odd textbooks I’ve done so far). At that point most edits seems to be slight clarification of wording, adding/revising pedagogical elements (boxes, sidebars, and such), and changing the exercises/problems. (But you would be surprised at the goobers I find that have survived several editions.)
If you’re truly concerned, the suggestion to check for reviews, etc. is excellent. If you can get your hands on a new or recent edition, look at the preface and other front matter, where the authors frequently outline what changes and updates have been made. Try the “Look inside this book” feature at Amazon – I sometimes go there to check out books I’ve worked on.
Here’s an example of a fast-paced field: astronomy. I tell my students that they should use the current edition of our textbook. If they complain that they already bought, borrowed, or stole an older edition, then I tell them to open the textbook to the index and look up “dark energy.”
Oh, it’s not there?
Hmmm. Well, if you insist, you can use that edition, but you might run into some trouble when we get to cosmology, and don’t come crying to me.
In physics texts, when they update the editions the major thing they do is change a bunch of the problems at the end of the chapters, so you’d be goofed up when you go to do the homework assignments, but it sounds like that’s not a concern.
Thats the thing. Some subjects like astrophysics or computers/robotics change rapidly. Other subjects like introductory calculus probably do not change at all anymore.
All I know is that alot of the stuff I am interested in inorganic chemistry was discovered and thought up in the 1930s. I do not know if major changes have been made since then but.
but I fear that I could be given incorrect info if I get a 30 year old textbook, even though alot of the theories were created in the 30s and 40s
I dunno.
My old high school textbooks seem accurate enough, except, isn’t Czechoslovakia now a democracy now?
Have you asked your professor yet? Most of my grad professors were well aware of any changes made between editions - and most would recommend older editions when they were available.
The best was my stats class, where the professor managed to scrounge up 35 1st editions from the 60s - all for about $10 a book, instead of the newer price of ~$75!
Myers Law : Only buy the even numbered editions.
Named for Colin Myers, late of University of Westminster, my old school. He reasoned like this: The first edition of any textbook contains errors. The second edition corrects the errors. The third edition contains new information, which is wrong. The fourth edition corrects the errors, etc.
I don’t know if I’m being whooshed, but Czechoslovakia doesn’t exist anymore.
On topic though… is there any way that you can find a book that they used last year? I know that on my students only message board, allmsu.com, there are always offers to sell books to individuals rather than bookstores, because it’s a better deal for everyone. Maybe you could find a discount at a similar type website. Even if it’s not the same edition, it would probably be closer than some book from 15-20 years ago.
This week in my Dynamics class, the teacher was working a problem and no one had any idea what he was doing. On investigation he discovered that problem #26 was different in the last edition, which he was working from, than problem #26 in the current edition, which we all had. Some subjects are difficult to study without adding avoidable variables.