An easy-to-use Japanese/English online dictionary.

Kodansha's Romanized Japanese-English Dictionary
PL 679 .V36 1993 (Reference)  Romanized entries in bold with hiragana, katakana, and kanji script equivalents. Many sentence examples and explanatory notes.

Kōjien (by I. Shinmura)
PL 675 .S49 1955 (LRA) A 1st edition of this venerable and popular dictionary. It contains ca. 200,000 headwords and numerous illustrations.

The Modern Reader's Japanese-English Character Dictionary (2nd ed.)
PL679 .N4 1974 (Reference)  Published in Rutland, Vt., this dictionary is organized with the English-speaking learner in mind. The 214 historical radicals form the basis of vocabulary lists that show characters, romanized spellings, and definitions. Required numbers of strokes are an additional organizing element. Many useful explanatory notes, lists, and charts.