A very intelligent family member of mine has recently decided to send me a large number of books and other resources on mathematics, include Hardy's book. Since this was published in 1921, is it still a useful textbook from which to learn pure mathematics?
Congratulations to such generous and wise members in your family. My answer is: Yes, of course. This text is great to read and will help to gain a deep and proper understanding of the material.
Hint: In order to better evaluate this treasure, the following might help to come to a decision by yourself:
It depends on your taste and interests. Many old books are fantastic, the age is not a problem. I personally dislike Hardy’s book and Hardy himself because I do not believe in “pure Mathematics”. Hardy’s disregard for applications seems to me arrogant and childish. You can learn Math from many other books that include nice motivations from Physics, Engineering etc. The older texts by Hermite, Goursat etc. Are more interesting in my opinion.