The Number Quadrata, Word Quadrata and Letters Quadrata puzzles in these books go from:
5 x 5 to 10 x 10 for numbers and 5 x 5 to 16 x 16
for the words and letters puzzles. You will only find the words puzzles in the books 
they are not available from this site.
You can try today's numbers and letters Quadrata puzzles by clicking Here.
For the uninitiated Quadrata puzzles are a square array of cells within which
values are placed such that no row or column has more than one of any value. This is known as a
Latin Square ('Quadrata' is the Latin for 'Square') because they were developed by the 18^{th}
century Swiss mathematician Leonhard Euler, using letters of the Latin alphabet, hence the name.
In newspapers, small, number versions of the puzzles have a variety of names such
as: 'Futoshiki' meaning 'inequality'; 'more or less'; and, so on, reflecting some of the clues
that are given.
Five is the most usual size that you will find in newspapers although there is
no reason why this cannot be extended both in terms of size and value to squares up to ten
along each side and, if using something with less of a constraint than the base value of our
counting system, to higher values still.
In the books, there are 250 Quadrata puzzles ordered in increasing difficulty:

100 number puzzles ranging in size from the familiar 5 x 5 square with numbers one to five,
up to a 10 x 10 square that starts at zero. By using numbers, you have a familiar set of values
that are already ordered so the inequality clues naturally make sense;

100 word puzzles where words that do not have any repeating letters have been used so that you
can still use an order that you can fairly easily become familiar with. These range in size
from 5 x 5 to 16 x 16. From 5 x 5 to 8 x 8, single words are used but from 9 x 9 to 16 x 16,
the order is specified by two words that between them use no letter twice; and,

50 word puzzles that use randomly selected letters, again ranging in size from 5 x 5 to 16 x 16.
In this case, however, there is no easy way to memorise the order of the letters.
So, whether you are yourself, a hardened puzzle junkie, someone who wants to become one or you need to find a gift
for somebody that is one, this is the only place you will find them.
Have Fun.