The Hebrew Root Movement is a messianic Christian group with some affinities with the Jehovah Witness group.  Their beginning goes back to the Seventh Day movements in the late nineteenth and early twentieth century (as do the Jehovah Witnesses).  Fortunately, they do not reject that Jesus is God as the Jehovah Witness do.  In principle, it is possible that a member of this movement could be a legitimate Christian, but it is very likely that they will deny you are a legitimate Christian.

This group does not have a central hierarchical structure, so it is difficult to make statements that apply to all in the movement, but generally they seek to impose Judaism on Christianity, and they do this even more than the JWs do.  They insist that the only name we can use for God is Yaweh and the only name we can use for Jesus is his Hebrew/Aramaic name Yeshua.  This is an absurd application of scripture, given the great number of names used for God and for Jesus in both the Old and the New Testaments.  Members of this movement also insist that Christians must observe Jewish festivals such as Passover, Pentecost and so forth as well as Jewish food laws.  They are very strong on sabbath observation. This group tends to be very legalistic.  They fail to notice that Jesus fulfilled the OT law (Matthew 5:17-19) and that we are no longer under obligation to the law of Moses (Coll 2:13-15) or that we are no longer required to observe Sabbaths and New Moons and the like (Colossians 2:16-18).  This group also rejects the decision of the Jerusalem Council in Acts 15:22-29 that Christians are not obligated to observe Jewish laws. This group does a VERY selective read of the scripture, ignoring a vast array of passages which show that we are not obligated to observe Sabbaths, dietary laws, Hebrew festivals, and the like.  They also fail to notice that if we are required to do these things, then we are also required to see a priest about skin diseases, to sacrifice bulls and goats, that we cannot wear clothing with two materials and many, many other things which they do not practice.  They are very selective and inconsistent in which of the laws of Moses they try to drag into Christianity.

I do not know about specific books written about this movement.  I do think that most any book you read about the Jehovah Witness group will apply almost equally to this group, as their mind-set is very similar.  I found a fairly balanced article which avoids using angry words or straw-man arguments and treats the group fairly.  Here is a link:  https://answersingenesis.org/presuppositions/dangers-hebrew-roots-movement/