It depends entirely on what you're looking for. If you're interested in the creation of the Imperial Japanese Navy and Army, then the best initial reads would likely be Evans and Peattie's Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy, 1887-1941 and the companion piece Sunburst: The Rise of Japanese Naval Air Power, 1909-1941 for the Navy, and Drea's Japan's Imperial Army: Its Rise and Fall for the Army. If you're interested in the air war in the first half of the conflict in the pacific, then one of the best would likely be Lundstrom's duology The First Team: Pacific Naval Air Combat from Pearl Harbor to Midway and First Team and the Guadalcanal Campaign: Naval Fighter Combat from August to November 1942, which are both excellent in depth looks at naval air combat during the opening phases of the war in the Pacific.

In terms of battle histories, one of the more easy to recommend ones is Parshall and Tully's Shattered Sword: The Untold Story of the Battle of Midway, for the Battle of Midway. For Pearl Harbor, it's easy to recommend the classic by Prange At Dawn We Slept: The Untold Story of Pearl Harbor, though I would pair that older work with Alan Zimm's Attack on Pearl Harbor: Strategy, Combat, Myths, Deceptions.

Of course, the war in the Pacific was not the only feature of the wider war with Japan. I found that S.C.M. Paine's The Wars for Asia, 1911–1949 to provide decent overall coverage for the Chinese Civil War and the Sino-Japanese War, but that's an area I'm not as well read on.

Finally, I'd also suggest Hasegawa's Racing the Enemy: Stalin, Truman, and the Surrender of Japan for some coverage on the final stages of the war in Japan.

Hopefully these suggestions help cover the area you're looking for.

There are always more recommendations that can be made, but the subreddit's booklist provides a great starting point with several options for you to look into.