Nintendo Power was a monthly print magazine focused on all things Nintendo. The magazine hit the scene in the late 1980s as a replacement for the free newsletter Nintendo Fan Club News. The first edition was released by Nintendo of America in the summer of 1988. In 2007, Nintendo of America contracted the publishing of the magazine to Future US. While the publication continued to deep-dive into game strategy and offer new release previews, the market for the magazine dwindled and Nintendo of America withdrew the licensing agreement from Future US in 2012.
Back issues of the magazine can be found on eBay. The best online resource is Nintendo Power Archive. The curator(s) of this website offer a glimpse into each edition.