After the fall of the Soviet Union, many high ranking Soviet officials were interviewed and asked about Soviet war planning, their protocols for use of nuclear weapons, their view of NATO, etc. These were compiled into a book called 'Soviet Intentions 1965-1985'. The book is dry as hell, but was filled with interesting nuggets, such as:
The Soviets came to the same conclusion as the West about the awful consequences of a full nuclear exchange, and Khrushchev especially was horrified at the thought of nuclear winter and global desolation.
Brezhnev could never say no. When asked to choose between two competing projects for a new missile, or interceptor, he would always accept both, much to the dismay of the economic planners who knew they probably couldn't even afford one project, let alone two.
I said no Avengers: Endgame spoilers, Comrade Motherfucker!
I just took a shit in my spacesuit, and I'm okay with that.
Some items of interest listed at RL:
The Soviets strove for nuclear superiority, especially in terms of numbers of ICBMs, because they believed that the United States was seeking to maintain the lead and that a failure to overtake Washington would "result in a serious negative gap in capabilities." [I: 2-13, II: 33 (Danilevich)]
The asymmetry between the U.S. and Soviet strategic triad was a special source of concern to the Soviets. They understood the U.S. insistence on crisis stability but they felt they had to keep developing the heavy land-based ICBMs that Washington considered destabilizing because they were cheaper to make and because the Soviet Union's geography did not allow for easy deployment of submarines. (See Document 3 at page 34)
Even when Moscow had more ICBMs than Washington, the Soviets did not feel secure because "they perceive[d] U.S. intentions to be aggressive and did not believe the superpower nuclear balance to be stable." For example, "virtually all interview subjects stressed that they perceived the U.S. to be preparing for a first strike." From satellite photography, the Soviets observed that U.S. missile silos were "relatively poorly protected by overhed cover and grouped rather close to each other and to the cluster's launch control center." The vulnerability of U.S. ICBM deployments convinced the high command that the ICBM "fields were first-strike weapons." [I: 1-2, 31; II: 100 (Kataev), 151 (Tsygichko)]
By the late 1960s, the Soviets accepted the concept that nuclear forces had a deterrence role. This meant that U.S. leaders would "not be allowed" to think that they could attack the Soviet Union without facing terrible consequences or to "feel such a sense of security that they would try to exercise their will in Europe with impunity." [I: 15-16]
Test of Soviet SS-18 (R-36) ICBM. (Kosmotras Web site) The Soviet military high command "understood the devastating consequences of nuclear war" and believed that nuclear weapons use had to be avoided at "all costs." In 1968, a Defense Ministry study showed that Moscow could not win a nuclear war, even if it launched a first strike. Although Soviet ideology had insisted that survival was possible, no one in the leadership believed it. In 1981, the General Staff concluded that "nuclear use would be catastrophic." [I: 23-24, 26; II: 24 (Danilevich), 124 (Mozzhorin)] This does not support arguments made by Richard Pipes in the late 1970s that the Soviets did not believe that a nuclear war would result in "mutual suicide" and that the "country better prepared for it and in possession of a superior strategy could win and emerge a viable society." (Note 1)
Before the 1970s, Soviet military officials paid no attention to the environmental impact of nuclear war, but they began to recognize that "drastic effects on climate" would be among the catastrophic effects of nuclear war (See document 5, "Stockholm Roundtable," p. 65). According to Dr. Vitalii Nikolaevich Tsygichko, a Senior Analyst at the Academy of Sciences, the author of the study, Mathematical Model of Soviet Strategic Operations on the Continental Theater (see document 4, with summary attached), and a former member of the General Staff, military analysts discussed the idea of a "nuclear winter" (although they did not use that term) years before U.S. scientists wrote about it in the 1980s. (Note 2) [II: 39 (Danilevich), 137, 139, 142 (Tsygichko).
During the early 1980s, according to the interviews, Fidel Castro recommended to the Kremlin a harder line against Washington, even suggesting the possibility of nuclear strikes. The pressure stopped after Soviet officials gave Castro a briefing on the ecological impact on Cuba of nuclear strikes on the United States. [I: 24; II: 28 (Danilevich)]
Questions raised over whether the Soviet "Dead Hand" automatic missile launch mechanism--the "doomsday machine"--ever became fully operational. It would have included mechanisms to launch automatically command missiles which would transmit launch orders to clusters of ICBMs. A manually activated system could launch the command missiles, but the Soviets also considered an automatic system where "triggering sensors were to launch the command missiles when excited by the light, or seismic shock, or radiation, or atmospheric density resulting from an incoming nuclear strike." General-Colonel Andran Danilevich declared that the Soviets "explored the possibility of such … systems, [but they] considered them too dangerous and unreliable and halted their development." Nevertheless, several of the interviewees stated that the automatic trigger system was deployed, but would be activated only during crises. [I: 19-21; II: 62-63 (Danilevich), 100-101 (Kataev), 107 (Korobushin); 134-135 (Surikov). (Note 3)
Believing that a U.S. surprise attack was possible, and that Soviet vulnerabilities made a retaliatory strike nearly impossible, during the 1960s Defense Minister Grechko and other military leaders sought capabilities to preempt an attack. Nevertheless, preemption was never a part of official Soviet military doctrine. Prime Minister Alexei Kosygin was a strong opponent of preemption and even the launch-on-warning strategy. According to testimony of Soviet witnesses, he "very categorically prohibited to even discuss that question." (See document 3 at page 26). Nevertheless, later in the decade, better understanding of the danger of nuclear war led political leaders to insist that the high command and defense industries make retaliation an option by hardening missile silos and improving warning and command and control systems (e.g. command missiles). Moreover, defense leaders put greater emphasis on launch-on-warning of attack, although preemption remained an option until Brezhnev renounced it in 1980. [I: 28-29, 34]
During the late 1970s and the 1980s, the Pentagon began to adopt strategies for limited nuclear options to make it possible to control escalation and reduce the risk of all-out nuclear war. The Soviets, however, were skeptical of limited options or the possibility of controlling escalation. While Soviet deterrence doctrine posited massive responses to any nuclear use ("all against any"), military officials considered the possibility of proportionate responses to a limited U.S. attack, although they "doubted that nuclear war could remain limited for long." [I: 37-39; II: 42 (Danilevich)]
Beginning in the mid-1970s, the Soviets followed a "no-first-use" policy; according to the interviews, "the Soviet Union never intended to initiate the employment of nuclear weapons." [I: 41; II: 5-6 [Akhromeev]
During the early 1990s, some analysts interpreted newly-available East German documents on Warsaw Pact military exercises as evidence that the Pact had a nuclear first-strike policy. The BDM analysts saw this interpretation as confusion between first-strike and "preemption"; the latter meant "attempting to strike an enemy that is preparing to a launch a nuclear strike before he is able to launch." Warsaw Pact and Soviet strategy consistently assumed that the United States would "be the first to prepare for nuclear use, and Soviet preemption would then occur in response to observations of NATO preparations." [I: 42; II: 74 (Gareev)] In fact, as also confirmed by the testimony of Soviet decision-makers and military experts, first strike was never part of Soviet military doctrine (See document 3, at pages 33-35, 39, Document 4, "Stockholm Roundtable," at p. 65)
Soviet models of a nuclear battlefield in Central Europe predicted that using 20 percent of the weapons deployed in the region would "throw millions of tons of toxic material into the atmosphere, causing an ecological disaster." (Note 4) Military operations would become impossible. "Nuclear strikes on all of NATO's airfields would contaminate Eastern Europe and parts of the Soviet Union." While the General Staff believed that nuclear weapons had little utility for combat operations, the Kremlin ordered the officers to make war plans using tactical weapons, although they never produced detailed plans. [I: 43-44] The reason for this inconsistency is the disconnect between the result of military studies and official Soviet doctrine, which postulated the historic inevitability of U.S.-Soviet confrontation, despite the desirability of peaceful co-existence, and the possibility of Soviet victory in a nuclear war. The assumption of the imperialist camp's inherent aggressiveness led to a situation where the Soviet leadership was trying to avoid war at all costs, but in the event of an actual U.S./NATO attack was willing to use any weapons in their possession. This scenario would turn any European conflict involving the use of tactical nuclear weapons into a full-blown nuclear exchange. Ironically, in the minds of the Soviet leaders this created a stronger deterrence because they were aware that their Western counterparts thought along the same lines.
Rather than making extensive preparations for battlefield nuclear combat in Central Europe, the General Staff emphasized conventional military operations believing that they had an advantage there. "The military leadership believed that conventional superiority provided the Warsaw Pact with the means to approximate the effects of nuclear weapons and achieve victory in Europe without resort to those weapons." [I: 44-45]
In the event of a conflict and NATO forces were about to overrun Soviet nuclear weapons sites and delivery systems, according to "standard operating procedure," the Soviets would "destroy them" with special devices and mines "rather than use them." [I: 44; II: 108 (Korobushin)]
The BDM analysts draw a startling picture of the decline of the Soviet leadership during the Brezhnev period, where the top people were "largely incompetent, indecisive, self-indulgent, and lazy." Beginning in the early 1970s Brezhnev's health was failing and after a massive stroke in January 1976 he fell into a state of total "inactivity." The vacuum at the top produced a situation where decisions on strategic forces devolved to the missile-building industry. (Note 5) According to the authors' sources, for guidance on strategic policy Brezhnev came to rely heavily on Professor Mstislav Keldysh, President of the Soviet Academy of Sciences, who opposed major investments in ABMs and supported arms control and more survivable ICBMs. [I: 50-52, 53; II: 82 (Illarionov)]
During the Brezhnev era, the top-level organizations for making decisions on defense policy, such as the Defense Ministry and the Defense Council, were mechanisms that rubber-stamped the preferences of the chiefs of military industries, who dominated the Military-Industrial Commission (VPK). Former officials "complained that [the VPK kept in production] obsolete weapons systems" and retarded "the development of advanced systems." Moreover, when defense industrial leader Dmitri Ustinov became Defense Minister, General Makhmut A. Gareev later observed, that meant that the armed forces had "been taken over by the enemy." [I: 57-60; II: 75 (Gareev)]
"The defense-industrial sector used its clout to deliver more weapons than the armed services asked for and even to build new weapons systems that the operational military did not want." An "internal arms race" developed in which design bureaus produced a variety of ICBMs with the same missions. When some called for a reduction of missiles, defense industry officials objected, because it would cause unemployment problems. [I: 61-63; II: 92 (Kalashnikov)]
See Related Link, that page seems to have most if not all of the book available in PDF format.