William of Ockham (1288 - 1348) was an English Franciscan friar and scholastic philosopher, from Ockham, a small village in Surrey.
Guillermo he was poor, he died for Black Death. He studied theology at the University of Oxford from 1309 to 1321, but never completed his master's. Because of this, he acquired the byname Venerabilis Inceptor, or Worthy Beginner (although he was also).A pioneer of nominalism, some consider him the father of modern epistemologyt and many scholars have thought that Ockham was summoned before the Papal court of Avignon in 1324 under charges of heresy,

The most importan works:

Philosophical writings

Summa logicae (c. 1323), Paris 1448, Bologna 1498, Venice 1508, Oxford 1675.
Quaestiones in octo libros physicorum, (before 1327), Rome 1637.
Summulae in octo libros physicorum, (before 1327), Venice 1506.
Quodlibeta septem (before 1327), Paris 1487.
Expositio aurea super artem veterem Aristotelis, 1323.
Major summa logices, Venice 1521
Quaestiones in quattuor libros sententiarum, Lyons, 1495.
Centilogium theologicum, Lyons 1495.
Theological writings
Questiones earumque decisiones, Lyons 1483.
Quodlibeta septem, Paris 1487, Strasbourg 1491.
Centilogium, Lyons 1494.
De sacramento altaris and De corpore christi, Strasbourg 1491, Venice 1516.
Tractatus de sacramento allans.

Political writings

Opus nonaginta dierum (1332), Leuven 1481, Lyons 1495.
Dialogus*, (begun in 1332) Paris 1476. Lyons 1495.
Super potestate summi pontificis octo quaestionum decisiones (1344).
Tractatus de dogmatibus Johannis XXII papae (1333–34).
Epistola ad fratres minores, (1334).
De jurisdictione imperatoris in causis matrimonialibus, Heidelberg 1598.
Breviloquium de potestate tyrannica (1346)
De imperatorum et pontifcum potestate also known as 'Defensorium'(1348)

links:

http://en.wikipedia.org/wiki/William_of_Ockham

http://plato.stanford.edu/entries/ockham/

http://www.wotug.org/parallel/www/occam/occam-bio.html