Chris Docker , Cheryl Smith, and the International Drugs Consensus Working Party 1993 (published internationally in several languages)
Departing Drugs is the ground-breaking publication from Exit that linked scientific evidence (published in the companion book, Beyond Final Exit) to recommendations on things like drug doses and the use of Exit bags. Evidence and 'how-to' instructions have now been very substantially updated and expanded.
Please note: Exit's current recommendation is to use our more recent publication 'Five Last Acts'. This is available on Amazon in two versions, Five Last Acts II and Five Last Acts - The Exit Path.*
Exit members living in the UK can also apply for Five Last Acts II at a slightly reduced rate (waiting period and proof of age required).
*The above links will take you to these books on Amazon's U.S. site. If you are ordering from outside the U.S., simply replace the ".com" with ".co.uk" or whatever the appropriate Amazon suffix is for your country. You can also just search under the title.