There seems to be confusion among some genealogists as to the difference between an Abstract, an Extract, a Transcript or Transcription and an Image Copy. Let's first define these terms:
Added March 5/11: EXTRACT: This is an exact copy of a portion of a document. Original spelling and grammar are retained
TRANSCRIPT & TRANSCRIPTION: This is an exact copy of a document. The entire document is written out exactly as found. No corrections or changes are made to the original. Punctuation, upper and lower case letters, any errors are kept as is. Misspellings are not corrected.
IMAGE COPY: A microfilm of a document. It could also be a photocopy, camera image or scan. Be careful to note whether the Image Copy is of an original document, transcript or extract.
Is it an exact copy of the original document, typed out or written out by a third party? If so, it's a Transcript or Transcription.
Perhaps you are looking at a microfilm of an original document (for example a church record or a census record). That is an image copy.
You might have found a book which gives summaries of wills. The full details of each will is not provided, but the book gives the main points - name of deceased, date of death, names of those mentioned in the will, date of signing and/or probate and names of witnesses. That is an
Added March 5/11: You've consulted a book which includes a quoted paragraph from a lengthy will. You are looking at an Extract. It's probably obvious that the best course of research accuracy is to consult an original. But if you can't find the original, your next best is a Transcript. You must keep in mind though that a transcript is only as accurate as the person who did the transcribing! They may have introduced errors, which is why it is always wise to make the attempt to find the original.
The last choice would be an abstract. Yes it will give you the important points (although it too may have errors or important omissions) but you are not getting complete details and may be missing out on something that will provide you with clues for further research.
The cautious researcher will be careful to note what type of record is being consulted.
Added March 5/11: With thanks to readers who corrected my explanation of EXTRACT and provided sources for their corrections.