Homophones and Homographs: An American Dictionary, 4th ed. in Bloomington, MN

This expanded fourth edition defines and cross-references 9,040 homophones and 2,133 homographs (up from 7,870 and 1,554 in the 3rd ed.).
As the most comprehensive compilation of American homophones (words that sound alike) and homographs (look-alikes), this latest edition serves well where even the most modern spell-checkers and word processors fail—although
rain, reign,
and
rein
may be spelled correctly, the context in which these words may appropriately be used is not obvious to a computer.