Back in the early 80's when the hobby was just getting started and I began my weekly trek down to War and Pieces in West Hartford. I stumbled upon Dragon Tree press and into the world of Delos.
Delos comes from the pens of Ben & Mary Ezzell.
From the Dragon Tree Home page :
Delos is a planet near neighbor to that best of all worlds which is Arduin®, and doth much traffic therewith. However the mana here is richer and more erratic, and the Theologian Newton describes it thus:
Here they need not store nor hoard their mana for it floats rich in the air for all, and nay they cannot hoard it for it slips and slides and sputters, all in and out of the Mage and the air and the ground and the Shadows. And here they cast and cast and there is no lack...and no grievous burden on the Mage to draw it neither. But as the mana slides about so often slide the spells and so they miscarry to the shame and sorrow of all....
American mages name this mana as 'Percentage and Fumble System'. The casters have aplenty to work with but tis like steering a ship in a storm or runaway horses, and caster's skill is all to turn it as he wishes and he fails to his woe.
Like Arduin®, Delos hath never built fireish machines but offtimes spaceships land here from the techno worlds and trade their goods or mayhap are robbed of them, and starrish beasties leave ship to roam in our woods. And here Multiversal can sell many strange goods from many strange worlds, but some they cannot sell because of the Prime Directive. And the rich living mana hereabouts offtimes sparks cross-Shadow making natural gates as those from England to Narnia, whence persons come through by mental inclining from amany strange Shadow-worlds and times, by the strength of their hearts' desires.
Introduction and description
Contains over 200 new magick items with complete descriptions, stats, prices, uses and misuses. Also included are rules for player-character construction of magick items in a mana-rich (i.e., Percentage and Fumble) world. Any first-level spellcaster can make a Staff of Power ... which will do something ... but watch out!