This is one of the early companion pieces to original Traveller, M & M is copyright 1981 and written with little consideration to the standard Third Imperium canon that was admittedly still in under development at the time, "... the Merchant Service. With traditions descended from the ancient Merchant Marine of Terra".
This book was intended to bring the Merchant career up to par with the "detailed" or "advanced" Army and Navy characters produced by Book 4 Mercenary and Book 5 High Guard, (in)famous for giving Characters 50% or more Skills than the original rules - Book 6 Scouts was still two years away, and Merchants and Merchandise was out a year in advance of the similar minded "Special supplement" for Merchants issued by GDW (and the full blown Book 7 Merchant Prince came out in 1985) so Donald Rapp certainly deserves quite a bit of credit.
M & M introduced several new Skills, including separate Jump Drive Engineering and Low Berth Maintenance, plus expanding on a couple of Skills recently introduced by Mercenary and High Guard. It used a variation of the pre-career College option, and detailed a Merchant Service Academy to prepare young men and women for the Galaxy (think young Lieutenant Grimes). Characters are tracked year by year, serving in a Division, possibly Cross-training or taking a Specialty School, etc.
One unique feature was that successive Specific Assignments, entitling a Character to a Skill gained, could span one, two or four years - which really made a kind of sense when compared to High Guard and Mercenary.
The Merchandise section includes a note that ties the products therein to their upcoming Vanguard Reaches, and Beyond sectors, "spinward" of GDW's two year old Spinward Marches, a seminal work in solidifying the canonical Third Imperium. The Eternity Circuit Module was a bizarre gimmick that seems to presage Nanite technology. There are four robots that are comparable to the robots in Adventure 2 - Research Station Gamma. There are two starships described, first the 150-ton Wind class noted as a modification of the 100-ton Serpent class Scout (as seen in Scouts & Assassins), the Winds are yachts or research/hospital ships with Jump 3 capability and accommodating up to 18 people (color-coded deck plan included). The other ship is a winged Far Trader featuring a Jump Governor [an outdated concept] and the "organic" computer that's the next Merchandise entry. There's also an explicit foray into ultra-tech with Matter Transporters ("to become a Transporter Specialist, an individual needs Navigation-1, Computer-1 and six weeks of training for familiarization. At the end of six weeks practice, throw 8 + for skill: DM'S for Intelligence 8+ (+1) , Dexterity 9+ (+ 2), and for each successive six week training session ..." )
As Adventure 4 - Leviathan - was (and is) one of my all time favorite Traveller settings Merchants & Merchandise was a great boost. It produced pretty interesting Merchant crew to blend with Scouts and Marines to fill our Merchant Cruiser as it probed the frontier.