Every learner of English carries a private list of words they can never keep apart, and the list is remarkably similar from one learner to the next. The words on it are almost never difficult words. They are short, ordinary words you have known for years. That is exactly the problem: they were filed together in your memory early, and nothing since has pulled them apart.
These mistakes survive everything. Your spellchecker will not flag them, because both words are real. Reading through on screen will not catch them, because your eye reads what you meant to write.
Every entry is labelled with the kind of confusion it causes — look-alike, sound-alike, close in meaning or grammar trap — and gives you the difference in one line, four example sentences (two for each word, side by side), a usage note, and the mistake shown wrong and then right.
250 pairs in 25 units of ten. Unit 1 is the ten that go wrong most often in written English. Units 2 to 20 are by subject. Units 21 to 25 cover look-alike spellings, sound-alike words, the short words that decide whether a sentence sounds native, the British and American pairs, and the modal verbs that look like one choice and are really two.
Each unit ends with a ten-question test — 250 in all — with a full answer key and an A-Z index of every pair at the back.
For learners at B1-C1, and for anyone who writes in English and would rather stop guessing.