Every white square hides a letter. Instead of clues, each square has a number, and each number always stands for the same letter. All 26 letters are used, each with its own number.
So if 7 is C, 14 is A and 3 is T, these squares spell CAT, and every other 7 in the grid is a C too:
You start with a couple of letters already filled in. Use them to guess a word, and every letter you find helps with the words that cross it.
Repeated numbers are a big clue. This word starts and ends with the same letter and has a double in the middle, so it might be NOON, DEED or TOOT:
If you already know 8 is O, it's NOON or TOOT:
There's a new puzzle most days, and older ones are in the archive.