An important - and particularly lengthy - article that Maestri contributed to "Gazzetta medica di Milano" focused on various aspects of the need for reform of the criminal justice system.

He nevertheless later claimed to have identified a risk, even in 1845, that Mazzini might succumb to "the usual tendency of [brilliant men], and substitute thoughts based on theory for the need for [simple] insurrectionary action".

[1] Back home in Milan, Maestri contributed to "Gazzetta medica di Milano" a lively set of "Reminiscences on the trip by a hypochondriac doctor to Paris and London".

[6] He is identified in the participants' listing as a "surgeon at the Milan Sanatorium" ("...medico chirurgo presso la casa de salute di della citta Milano").

Maestri teamed up with Romolo Griffini to launch "Voce del popolo" ("Voice of the people"), a daily tabloid-sized newspaper published in Milan between 26 March and 29 July 1848, with a cover price of 5 centesimi.

The relatively conciliatory spirit in respect of moderate-liberal opinion was summed up in a strikingly "constructive mission statement" printed and signed by the two editors on 26 March 1848: "Our political approach, for now, is to be helpful, supportive and obedient to the provisional government" ("Il nostro motto politico è, per ora, aiuto, soccorso, obbedienza al Governo provvisorio").

[2] Towards the final part of Milan's summer of independence, on 7 July 1848, Maestri was summoned to become a member of the "Extraordinary Central Committee for arming the national guard[b] In 28 July 1848 Pietro Maestri, together with Francesco Restelli and Manfredo Fanti, joined the "Committee of Public Safety" which struggled in vain to organise resistance against the Austrian army, now greatly reinforced recently victorious against Charles Albert of Sardinia at Custoza.

[1] Through the preceding four months Maestri had vented an implacably republican opposition to any merger of Lombardo-Veneto into the neighbouring Kingdom of Sardinia-Piedmont (which had emerged from the Napoleon nightmare with its autonomy formally intact).

Nevertheless, in the 60 page booklet he produced with Francesco Restelli on 15 August 1848, providing a factual but emotionally charged account of the sad events that marked an end to Milan's summer of independence, Maestri was bitterly critical of King Charles Albert of Sardinia, accusing the Sardinian leader of "treachery", on account of the Sardinian army's failure to resist the Austrian recapture of Milan more effectively.

[12] In Florence between November 1838 and January 1849 he was a leading promoter of the Provisional Central Committee created as a precursor to a National Constituent Assembly in Rome where, during the early months of 1849, he was one of the most prominent supporters of that development.

The idea of a merger between the Roman Republic and Tuscany, which would have further antagonised Austria, failed to gain significant traction with the most powerful member of the governing trio, Francesco Domenico Guerrazzi, who at the end of March 1849 had his role within the triumvirate strengthened when he accepted the title of "dictator", apparently with the support of the French government, which viewed the continuing political crisis on the Italian peninsula with intensifying concern.

After Rome was surrendered to the French at the start of July 1849, and with the Grand Duke returned to power in Florence through the threat of an imminent Austrian invasion at the end of the same month,[15] In Milan, with the Austrians firmly back in control, the so-called "Radesky Proclamation", issued on 12 August 1849, included a lengthy listing of Milanese who would not be able to return home "because of their unjustifiable perseverance in support of revolution and their subversive tendencies".

The failure of the Milanese uprising of 1848 to trigger the transformation of most or all of the Italian peninsula into an independent republic dedicated to the ideals of liberalism and democracy was a defining disappointment to the patriot generation of 1848: the two and a half years that followed, exiled in Turin, provided an opportunity to take stock.

Convinced that a successful launch of Italian democracy should and would need to be based on socialist principals of the time, the men now accused Mazzini, Maestri's former mentor, of what they termed "formalismo", because they thought it had become clear that the Mazzinian vision for Italy totally ignored the social dimension.

[1][17] Of particular significance during this period was a thoughtful contribution that Maestro produced for the 1851 edition of the Turin "Annuario economico-politico" (loosely, "Economic-Political Yearbook") which signals the start of Maestri's development, during the later 1850s, from political activist and street fighter to student of the re-emerging discipline of Statistics and influential politic-economic commentator.

[1] Although there is mention of his having worked as a physician, in terms of his public footprint the focus of Maestri's life in Paris was on his engagement as a student-scholar of Statistics and on his associated journalistic output.

Maestri enlisted as a doctor-surgeon with Garibaldi's "Cacciatori delle Alpi" brigade, a proto-partisan operation created to support the Sardinian-Pietmontese army in the struggle to liberate Northern Italy.

He also did valuable work as an intermediary between Agostino Bertani, chief medical officer of the "Cacciatori delle Alpi" and Count Cavour (who was in effect serving as his own Minister for War in the government that he led in Turin).

The French dictator loved to take his allies and enemies by surprise, and when he unexpectedly concluded an armistice with the Austrian emperor on 11 July 1859 it meant, to the bitter disappointment of Garibaldi, Cavour and their supporters, that the fighting was over.

In September 1859 Pietro Maestri returned to Paris and resumed his life as an increasingly prominent commentator on the twin themes of politics and economics, primarily with respect to Italy.

In an article published in "Gente latina" on 7 November 1859 (and in other contributions in other publications dating from around the same time) he positioned himself in opposition to the excessive "top down" centralising philosophy apparent in the way that the Cavour government in Turin sought simply to incorporate the western half of what had been Lombardo-Veneto into what was left of the Kingdom of Sardinia.

[f] Maestri recommended, instead, a "régime combining political unity and administrative decentralisation" which both the ancient and the newly acquired provinces of the "Savoyard monarchy" would have to accept "as the practical route to [Italian] unification".

There was something tantalisingly logical and pre-packaged in Napoleon's blueprint for a modern European state, but for Pietro Maestri the centralising model that so appealed to Cavour and his king was quite unsuitable (except, perhaps, for France).

[1] According to at least one source, on 21 April 1862 Maestri was still living in France when he was appointed by royal decree to a post as head of the Statistics Directorate which had been established the previous year at the Ministry of Agriculture, Industry and Commerce.

A section of it was expressly dedicated to the statistics of municipal authorities, a particularly timely concern during a period in which, in many countries and regions of western Europe, agricultural depression caused by newly transportable food imports from America, along with the lure of wage levels that were generally higher and more consistent in the factories than in the fields, meant that urban dwellers were outnumbering rural dwellers for the first time in history.

He also continued frequently to team up with Cesare Correnti to take a lead in organising the National Statistical Council (la "Giunta centrale di statistica") and in other data collection projects.