I find it interesting that you cite both Fukuyama and Ferguson in a search for 'neutral/objective' history books. Fukuyama, of course, is widely known for The Death of History which is one of the most well known treatises on neoliberal international relations theory, arguing against both post-modernist political thought and (to a large degree) IR realism. Ferguson is a well known contrarian who likes to argue against widely held beliefs. He also, somewhat controversially, is a proponent of a version of 'great man theory' in history that until Ferguson came along was widely dismissed in most academic circles (and still is, in fact). This offers a good chance to talk about schools of historical thought, and theory for a moment.

The study of anything in the social sciences generally breaks down into multiple schools, which at its core level are a way to explain, and predict with a certain level of reliability. In history this is important because the study of history is not a simple listing of dates and events in the past without context. It is also very much the study of why and how those events happened. Thus knowing that the March on Rome began on 22 October 1922 is less important than knowing why the Fascists did so. This is where schools of thought, and theory come into play. The easiest way to explain this is how if you asked 10 people on the street why the Falcons just lost the Super Bowl you would get roughly ten different answers. Within those answers though you would notice common thoughts and theories.

Perhaps a few thought that it's because Tom Brady is just that good of a quarterback and all forces revolve around him. Perhaps a few thought it's because the systems that the Patriots have in place have produced just that much better of a team. A few may think that the shared set of values of the Falcons and Patriots opposing each other produced the outcome. Perhaps a bearded one off to the side will comment it's because the system is rigged against the working team and they need to seize the means of production. You may notice that it's next to impossible to decide which one of these was right or wrong, you can only make arguments if you accept of disagree with their conclusions.

Those are historical schools of thought (the study of which is historiography). They are the ways in which historians interpret history. They are also heavily important to understand because they will then give weight to what the historian considers important, and what the historian doesn't consider important. In the American Consensus School importance is (broadly) given to structure, and a shared set of values and agreement. New Left historians, on the other hand, (broadly) emphasize the significance of conflict between different groups, and give more focus to those not in the mainstream of agreement. Fukuyama, mentioned above, can broadly be considered a liberal within international relations theory, which gives more autonomy and authority to the individual, at the expense of the power of the state. This is contrary to IR theory realism, on which the state is a unitary actor with ultimate power. Which is further contrary to dependency theory which states that the world structure (both states AND individuals) is dominated by capitalistic societies at the expense the underdeveloped.

This is a long way of saying that any decent book on history is going to be "biased" and not as "neutral/objective" as you may think. Which leads into your question on books on the rise of Fascist parties. I can only speak for Italian fascism but there is plenty of divide in historical schools of thought on the 'what,' 'how, and 'why' of fascism. Historians on Italian fascist history will, more or less, devolve into holy wars (broadly speaking) on if Fascism was a reactive movement, or if it was an assertive movement. This leads to no small amount of arguing, and massively different interpretations of different events. This leads to a natural question: was there unrest in Italy during and after World War One because of the outcome of the war, or was the outcome of the war the result of unrest in Italy? Depending on your school of thought and interpretation, both are correct answers.

The best book, that gets as close to the 'neutral/objective' account that I can offer is Denis Mack Smith's Modern Italy: A Political History which gives a fairly reliable accounting on the basics of the circumstances, politically speaking, which lead to fascism's rise. David Kertzer's Pulitzer Prize winning The Pope and Mussolini is a surprisingly useful accounting as well that gives heavy background into Mussolini's hand in the rise of the PNF. R.J.B. Bosworth goes through the historiography controversies in Italian fascism in The Italian Dictatorship: Problems and Perspectives in the Interpretation of Mussolini and Fascism which both deconstructs and reassembles much of the schools of thought when it comes to studying the Mussolini years.

For Spain, the foremost expert is Stanley Payne. His fundamental works:

Payne, The Franco Regime, 1936-1975: an excellent discussion not just of the regime itself but of the construction of the political party structures and state apparatuses, both during and immediately following the Spanish Civil War.

Payne, Fascism in Spain, 1923-1977: This book limits its analysis to discussion of the Falange, the "true" Spanish fascist party. Payne makes it a point to make a clear distinction between the Falangists as the "real" fascists in Spain in contrast to other factions within the Franco regime, which consisted of conservative monarchists (Alfonsine and Carlist), and later social Catholic technocrats.

That being said, there is a lot of debate among Spanish historians about whether it is appropriate to only consider the Falangists as the "real" exponents of Spanish fascism. Other historians have been more willing to accommodate Francoism's conservative and monarchical wings into broader analyses of the phenomenon of European fascism. One such historian who is comfortable situating Spanish militarist monarchism within an analysis of European fascism is Alejandro Quiroga, who looks at the Spanish state's attempt to nationalize the masses under the dictatorship of Miguel Primo de Rivera in the 1920s (1923-1930). Quiroga argues a direct link between Primoriverista fascism in the 1920s and Francoism in the 1940s. Furthermore, Quiroga makes frequent comparisons between Primo de Rivera's regime and Mussolini's. It should also be pointed out that Primo de Rivera seized power in Spain in a coup in 1923 but a few months after Mussolini took power in Italy in 1922, and utilizing similar strategies. Mussolini traveled to Spain in the 1920s in a high-profile state visit and Primo confessed to be a big fan of Mussolini's ideas. Primo modeled many of his governmental and political party structures on the principles of Italian corporatism and vertical syndicalism.

Quiroga's book: Alejandro Quiroga Making Spaniards: Primo de Rivera and the Nationalization of the Spanish Masses, 1923-1930

To conclude, a good analysis of Spanish fascism will take into account Spain's longer trajectory of praetorian and militarist politics, integrating both an analysis of Primo de Rivera's regime AND Franco's. Payne and Quiroga give you a good balance of the different sides of the debate. Payne is more precise and careful in his analysis, arguing that Spanish fascism never seriously took root in Spain, but was offered a platform as part of a coalition of mostly conservative monarchists who came to power in civil war. Franco dressed his regime up in fascist trappings but was mostly an authoritarian conservative. Quiroga, conversely, tilts more toward the argument that the Spanish right was more explicitly fascist than perhaps other historians will allow and that one can find evidence of such an identification by looking to the Primo de Rivera regime.