Linear B is the script that was used for writing Mycenaean, an early form of the Greek language.
It occurrs primarily on tablets dated from the 14th and 13th centuries BC. The script was derived from an earlier script (Linear A) used for writing the Minoan language and thus does not accurately represent the sounds of the Mycenaean language. It is partly syllabic, with additional logographic signs.

The first clay tablet at Knossos was discovered by the British archaeologist Arthur Evans on March 31, 1900 and on April 6 he discovered a significant hoard of tablets (measuring 5x10 inches).

Michael Ventris deciphered Linear B in 1951-1953.

Linear B has roughly 200 signs, divided in syllabic signs with phonetic values and logograms (or ideograms) with semantic values.

Linear B is assigned Unicode Range 10000-1007F for syllabic signs and 10080-100FF for logograms.

syllabic signs

The names of these signs are only roughly phonetical, since most are used to represent a whole class of syllables each, see Mycenaean language. There are some additional, mostly rare, syllabic signs, the values of some of which are unknown or disputed. They are referred to either by a number, or by some hypothetical phonetic approximation, e. g. a2, a3, au, nwa, pu2 etc.

logograms

Due to the nature of the texts preserved, logographic representations of items counted are very frequent. Not all of their values are known, and their pronunciation is, at best, the object of educated guessing.
The logograms represent concepts such as MAN, WOMAN, COW, BULL, OIL, WINE, CLOTH, GOLD, BRONZE etc. There are several dozen signs representing various kinds of pots and vessels.

Also see other discoveries