Transmission is written and maintained by:

Eric Petit <titer@m0k.org>
 + Back-end
 + OS X interface

Josh Elsasser <josh@elsasser.org>
 + Back-end
 + GTK+ interface

Mitchell Livingston <livings124@gmail.com>
 + OS X interface

Bryan Varner <bryan@varnernet.com>
 + BeOS interface

Michael Demars <keul@m0k.org>
 + OS X interface (Growl notifications, AppleScript)

Translators:

Calorì Alessandro
 + Italian GTK+ translation

Pierre-Henri Quelen
 + French GTK+ translation

Vicente Carro Fernandez
 + Spanish GTK+ translation

Thanks to:

Omar and Adrien
 + Beta testing

Various people
 + Writing http://wiki.theory.org/BitTorrentSpecification

vi@nwr.jp
 + Free SHA1 implementation (sha1.[ch])

John Blitch
 + OS X patch (Contextual menu)

Ahmad M. Afuni
 + NetBSD patch

Jeremy Messenger
 + FreeBSD patch

Mike Matas <http://www.mikematas.com/>
 + OS X toolbar icons

Martin Stadtmueller
 + Icon tweaking

FOOOD
 + Badging images, Progress Bar images

Nick Pucius
 + Mac OS X Help documentation

Rashid Eissing
 + Transfers preferences icon
 + Interface conceptualization

Deanna Phillips
 + Manpage for transmissioncli

Thanks to M. Uli Kusterer for use of UKKQueue.