Problem-Solving Strategies (Problem Books in Mathematics) Paperback – Illustrated, 12 Dec. 1997

a classic book in mathematical olympiads !

It used to be the holy grail of math competitions but nowadays is over-read and so a bit outdated as a study companion. You can borrow it from your university library or a professor instead of buying it, get hands on experience on the topic and keep your money to buy something else. Highly recommend books from Titu Andreescu.

The book is useful for the sheer number of problems that it contains. However the solutions are often incorrect, and the problems are sometimes incorrectly stated, asking students to prove things that are actually false, leading to much confusion. It is certainly not worth the large price, but a pdf is available online which is great for the number of problems it contains.

The book is a compendium of mathematics problems from olympiad competitions and similar contexts. The approach of the editor is very poor and full of errors. Some demonstrations are incomplete and wrong. I do not recommend it at all