Bird's Opening is currently in that 'Goldilocks' zone of the great arbitrages in life. The majority of chess players have dismissed it overlooking its inherent value and this allows for adopters of the Bird to take advantage of this asymmetry. As of this writing, it is played 0.9% of the time in online databases and this drops to 0.2% (!) in the master's database of OTB games. For reference in the OTB database 1.e4 is played 45% of the time. So for every 225 OTB games your opponent plays against 1.e4, he plays against the Bird once. While a case could be made that 1.e4 or 1.d4 are stronger, the objective difference between them and the Bird is infinitesimal. The way I see it, people will continue to ignore the Bird for the foreseeable future. Unless this book sells a million copies, the Bird will never be played remotely close to the frequency it deserves. Because of this it will never be worth your opponent's while to study it, so it will always carry great surprise value. The book is structured around the Lichess database for players rated between 1200 and 2000 - so if you are in this category the repertoire will synchronize perfectly with the lines your opponents are choosing in your own games. Whenever possible I have sought out lines to surprise your opponent and give them the toughest time figuring things out.