Only Jesus is worthy.
And they sung a new song, saying, Thou art worthy to take the book, and to open the seals thereof: for thou wast slain, and hast redeemed us to God by thy blood out of every kindred, and tongue, and people, and nation; (Revelation 5:9 KJV)
Imagine seeing this scene play out in Heaven. The Lamb who was slain Jesus Christ is the only one worthy to open the seals opens the book of Life because He was slain and was The Sacrifice God sent to redeem sinful mankind. He is the only one with the authority to open the seals of this important book.
The Bible tells us this spiritual event will be done in the presence of elders surrounding the throne. It is not known who these elders will be but certainly they are chosen representatives of His church who lived and served Him upon this earth. These elders are described as singing songs of praise to God as He cracks open this significant book. We cannot even fathom or imagine from our limited earthly perspective this heavenly scene or hear how joyous singing will be; even more beautiful and filled with wonderful harmony being greater than any song we have thus far heard on this earth as the Bible tells us it is a new song never before heard.
The identity and purpose of this heavenly book is not made clear other than it has great importance. Perhaps it is the deed or certificate of ownership of this earth handed over to God as the world comes to an end, or contains the judgments of men, or perhaps the rewards of those who served God upon this earth.
Have you spent time reading about Heaven and Hell and eternity in the book of Revelation? It is the only book which promises a blessing to those who read it. It contains many events and descriptions of the heavenly realm which man, in his limited perspective, cannot begin to fathom.