I collect 1st edition fantasy & sci-fi. No idea how many I have, but the bookshelves are full
Condition is everything. If the pages are yellow, folded or creased it's worth less. Broken or damaged spines are a big no-no. Basicaly a collector wants a book that looks as though it's never been read.... in fact a fair few of my first editions never have been... I have a second or paperback edition to read, and the 1st is never opened.
A missing dust jacket is going to reduce the value by something in the region of 30-50% it's a major collection point.
You can check
www.bookfinder.com for dealer prices. Most of the prices quoted are at the higher end of the market - knock off 20% and you should get an idea of the actual going rate. Most entries will quote a condition
New/Mint - Never been read - still in celophane.
Excellent - Just looks like its never been read, no marks folds, creases or stains
Very Good - some minor marks or minor creasing to spine, minor page yellowing.
Good - more extensive marking, creases to pages, cracked spine but still intact (this is what most peoples book look like after they've been read a couple of times)
Average - some damage, loose pages folds etc. may have missing dust covers
Poor - heavy staining, missing pages, ripped covers etc.
The age of the book also affects the condition - no one expects a 18C book to be in the same condition as a 5yr old 1st.
Also, check that it really is a first edition/first imprint - they are the collectable ones. The print dates should help with the edition on older books. Newer books will usually have the imprint shown in a number line somewhere on the publisher page the number line will look like 9 8 10 6 3 2 1 4 5 7 or similar - the lowest number shown indicates the imprint number. Unless its a first (or has some notable fault or rarity) then its much less collectable.
