Finding a legal PDF copy of this book requires a bit of navigation, as a free, official version is not publicly distributed by the publisher. Here is a breakdown of the best avenues to explore:
: A sequel that specifically analyzes BMO1 problems from , serving as a continued practice guide for students who have finished the first book. A Mathematical Olympiad Companion a mathematical olympiad primer pdf
If you are a secondary student aiming for your first qualification, this is arguably the best "first book" to buy. It focuses on the specific skillset required for UKMT competitions rather than general mathematical theory. Finding a legal PDF copy of this book