TITLE: About a letter by Richard Palais of 1965.
QUESTION [42 upvotes]: In Cushman and Bates, Global Aspects of Classical Integrable Systems, 1997, I have read 

In a widely circulated but unpublished letter in 1965, Palais explained the symplectic  formulation of Hamiltonian mechanics.

I would like to know if, in the meanwhile, this letter was made available.

REPLY [114 votes]: I haven't thought about that letter for a very long time, but as far as I can recall I didn't ever make it publicly available, and I don't think any of the friends to whom I sent it did either. However, I am a bit of a pack-rat, so after Ryan Budney alerted me that this question had appeared on MO I did some searching in my piles of old papers, and I found and scanned what I am pretty sure was the mathematical content of the letter, and here is a link to the scan. 
http://vmm.math.uci.edu/PalaisLetterOnSymplectic.pdf
(I'm not sure if I just sent out copies of this with a cover letter or rather wrote a letter in which I copied the contents of the above.)
Note, that the first page of the above is a scan of page 159 of "Foundations of Mechanics" by Ralph Abraham and Jerry Marsden. It says that the letter was from around 1962, which is what I recall. Ralph was one of the recipients.  Dick Palais

REPLY [15 votes]: I would like to know if, in the meanwhile, this letter was made available

Yes! (See here).