Whether you need the book or not everyone must have to decide for yourself. Who can have a little talk for a while or want to laugh with a few Bros a bit, which is have some fun. Who dagen, 200 fully-written pages, will probably be disappointed, because for each article of the code an entire page is reserved and since they are not necessarily more than one (!) Set to "The Bro Code" also reads quite fast.
But, and this must be emphasized at this point: it's fun anyway. There you will find highlights such as a scale the degree of madness Ladies or two Bros should behave when they have simultaneously seen a pretty lady (eg. Is paper, rock, scissors to use). Might sound without background knowledge from the series somewhat absurd, but who would also be the "Bro Code" bring no "How I Met Your Mother" to know?
Conclusion: Distractions book for times in between or to laugh with friends. But you should not expect serious literature. Highly recommended!